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Fungi
Fossil range: Early Devonian – Recent (but see text)
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A collage of five fungi (clockwise from top left): a mushroom with a flat, red top with white-spots, and a white stem growing on the ground; a red cup-shaped fungus growing on wood; a stack of green and white moldy bread slices on a plate; a microscopic, spherical grey-colored semitransparent cell, with a smaller spherical cell beside it; a microscopic view of an elongated cellular structure shaped like a microphone, attached to the larger end is a number of smaller roughly circular elements that collectively form a mass around it
Clockwise from top left: Amanita muscaria, a basidiomycete; Sarcoscypha coccinea, an ascomycete; bread covered in mold; a chytrid; a Penicillium conidiophore.
Scientific classification
Domain: Eukarya
(unranked): Opisthokonta
Kingdom: Fungi
(L., 1753) R.T. Moore, 1980[1]
Subkingdoms/Phyla/Subphyla[2]
Blastocladiomycota
Chytridiomycota
Glomeromycota
Microsporidia
Neocallimastigomycota

Dikarya (inc. Deuteromycota)

Ascomycota
Pezizomycotina
Saccharomycotina
Taphrinomycotina
Basidiomycota
Agaricomycotina
Pucciniomycotina
Ustilaginomycotina

Subphyla Incertae sedis

Entomophthoromycotina
Kickxellomycotina
Mucoromycotina
Zoopagomycotina

A fungus (pronounced /ˈfʌŋɡəs/) is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The Fungi (pronounced /ˈfʌndʒaɪ/ or /ˈfʌŋɡaɪ/) are classified as a kingdom that is separate from plants, animals and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. These and other differences show that the fungi form a single group of related organisms, named the Eumycota (true fungi or Eumycetes), that share a common ancestor (a monophyletic group). This fungal group is distinct from the structurally similar slime molds (myxomycetes) and water molds (oomycetes). The discipline of biology devoted to the study of fungi is known as mycology, which is often regarded as a branch of botany, even though genetic studies have shown that fungi are more closely related to animals than to plants.

Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil, on dead matter, and as symbionts of plants, animals, or other fungi. They may become noticeable when fruiting, either as mushrooms or molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange. They have long been used as a direct source of food, such as mushrooms and truffles, as a leavening agent for bread, and in fermentation of various food products, such as wine, beer, and soy sauce. Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungi are also used as biological agents to control weeds and pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals including humans. The fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases (e.g. rice blast disease) or food spoilage can have a large impact on human food supplies and local economies.

The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from single-celled aquatic chytrids to large mushrooms. However, little is known of the true biodiversity of Kingdom Fungi, which has been estimated at around 1.5 million species, with about 5% of these having been formally classified. Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus, Christian Hendrik Persoon, and Elias Magnus Fries, fungi have been classified according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the last decade have helped reshape the classification of Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla.

Contents

Etymology

The English word fungus is directly adopted from the Latin fungus (mushroom), used in the writings of Horace and Pliny.[3] This in turn is derived from the Greek word sphongos/σφογγος ("sponge"), which refers to the macroscopic structures and morphology of mushrooms and molds; the root is also used in other languages, such as the German Schwamm ("sponge"), Schimmel ("mold"), and the French champignon and the Spanish champiñon (which both mean "mushroom").[4] The use of the word mycology, which is derived from the Greek mykes/μύκης (mushroom) and logos/λόγος (discourse),[5] to denote the scientific study of fungi is thought to have originated in 1836 with English naturalist Miles Joseph Berkeley's publication The English Flora of Sir James Edward Smith, Vol. 5.[4]

Characteristics

Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the Plant Kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile, and have similarities in general morphology and growth habitat. Like plants, fungi often grow in soil, and in the case of mushrooms form conspicuous fruiting bodies, which sometimes bear resemblance to plants such as mosses. The fungi are now considered a separate kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago.[6][7] Some morphological, biochemical, and genetic features are shared with other organisms, while others are unique to the fungi, clearly separating them from the other kingdoms:

Shared features:

Unique features:

  • Some species grow as single-celled yeasts that reproduce by budding or binary fission. Dimorphic fungi can switch between a yeast phase and a hyphal phase in response to environmental conditions.[19 ]
  • The fungal cell wall is composed of glucans and chitin; while the former compounds are also found in plants and the latter in the exoskeleton of arthropods,[20][21] fungi are the only organisms that combine these two structural molecules in their cell wall. In contrast to plants and the oomycetes, fungal cell walls do not contain cellulose.[22]
A whitish fan or funnel-shaped mushroom growing at the base of a tree.
Omphalotus nidiformis, a bioluminescent mushroom

Most fungi lack an efficient system for long-distance transport of water and nutrients, such as the xylem and phloem in many plants. To overcome these limitations, some fungi, such as Armillaria, form rhizomorphs,[23] that resemble and perform functions similar to the roots of plants. Another characteristic shared with plants includes a biosynthetic pathway for producing terpenes that uses mevalonic acid and pyrophosphate as chemical building blocks.[24] However, plants have an additional terpene pathway in their chloroplasts, a structure fungi do not possess.[25] Fungi produce several secondary metabolites that are similar or identical in structure to those made by plants.[24] Many of the plant and fungal enzymes that make these compounds differ from each other in sequence and other characteristics, which indicates separate origins and evolution of these enzymes in the fungi and plants.[24][26]

Diversity

Fungi have a worldwide distribution, and grow in a wide range of habitats, including extreme environments such as deserts or areas with high salt concentrations[27] or ionizing radiation,[28] as well as in deep sea sediments.[29 ] Some can survive the intense UV and cosmic radiation encountered during space travel.[30] Most grow in terrestrial environments, though several species live partly or solely in aquatic habitats, such as the chytrid fungus Batrachochytrium dendrobatidis, a parasite that has been responsible for a worldwide decline in amphibian populations. This organism spends part of its life cycle as a motile zoospore, enabling it to propel itself through water and enter its amphibian host.[31] Other examples of aquatic fungi include those living in hydrothermal areas of the ocean.[32]

Around 100,000 species of fungi have been formally described by taxonomists,[33] but the global biodiversity of the fungus kingdom is not fully understood.[34] On the basis of observations of the ratio of the number of fungal species to the number of plant species in selected environments, the fungal kingdom has been estimated to contain about 1.5 million species.[35] In mycology, species have historically been distinguished by a variety of methods and concepts. Classification based on morphological characteristics, such as the size and shape of spores or fruiting structures, has traditionally dominated fungal taxonomy.[36] Species may also be distinguished by their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals, or their reaction to chemical tests. The biological species concept discriminates species based on their ability to mate. The application of molecular tools, such as DNA sequencing and phylogenetic analysis, to study diversity has greatly enhanced the resolution and added robustness to estimates of genetic diversity within various taxonomic groups.[37]

Morphology

Microscopic structures

Microscopic view of several purple-stained cells with two thick, dark purple lines and small dark purple circles near the lines
A hypha of Hyaloperonospora parasitica (downy mildew) growing within the leaf tissue of Arabidopsis thaliana. The long structure is the hypha, and the little spheres are haustoria, which extract nutrients from the plant cells.

Most fungi grow as hyphae, which are cylindrical, thread-like structures 2–10 µm in diameter and up to several centimeters in length. Hyphae grow at their tips (apices); new hyphae are typically formed by emergence of new tips along existing hyphae by a process called branching, or occasionally growing hyphal tips bifurcate (fork) giving rise to two parallel-growing hyphae.[38] The combination of apical growth and branching/forking leads to the development of a mycelium, an interconnected network of hyphae.[19 ] Hyphae can be either septate or coenocytic: septate hyphae are divided into compartments separated by cross walls (internal cell walls, called septa, that are formed at right angles to the cell wall giving the hypha its shape), with each compartment containing one or more nuclei; coenocytic hyphae are not compartmentalized.[39] Septa have pores that allow cytoplasm, organelles, and sometimes nuclei to pass through; an example is the dolipore septum in the fungi of the phylum Basidiomycota.[40] Coenocytic hyphae are essentially multinucleate supercells.[41]

Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include haustoria in plant-parasitic species of most fungal phyla, and arbuscules of several mycorrhizal fungi, which penetrate into the host cells to consume nutrients.[42]

Although fungi are opisthokonts—a grouping of evolutionarily related organisms broadly characterized by a single posterior flagellum—all phyla except for the chytrids have lost their posterior flagella.[43] Fungi are unusual among the eukaryotes in having a cell wall that, in addition to glucans (e.g., β-1,3-glucan) and other typical components, also contains the biopolymer chitin.[44]

Macroscopic structures

Fungal mycelia can become visible to the naked eye, for example, on various surfaces and substrates, such as damp walls and on spoilt food, where they are commonly called mold. Mycelia grown on solid agar media in laboratory petri dishes are usually referred to as colonies. These colonies can exhibit growth shapes and colors (due to spores or pigmentation) that can be used as diagnostic features in the identification of species or groups.[45] Some individual fungal colonies can reach extraordinary dimensions and ages as in the case of a clonal colony of Armillaria ostoyae, which extends over an area of more than 900 ha, with an estimated age of nearly 9,000 years.[46]

The apothecium—a specialized structure important in sexual reproduction in the ascomycetes—is a cup-shaped fruiting body that holds the hymenium, a layer of tissue containing the spore-bearing cells.[47] The fruiting bodies of the basidiomycetes and some ascomycetes can sometimes grow very large, and many are well-known as mushrooms.

Growth and physiology

The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high surface area to volume ratios.[48] Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues.[49] They can exert large penetrative mechanical forces; for example, the plant pathogen Magnaporthe grisea forms a structure called an appressorium which evolved to puncture plant tissues.[50] The pressure generated by the appressorium, directed against the plant epidermis, can exceed 8 MPa (80 bars).[50] The filamentous fungus Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes.[51]

Time-lapse photography sequence of a peach becoming progressively discolored and disfigured
Mold covering a decaying peach. The frames were taken approximately 12 hours apart over a period of six days.

The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol.[52] Morphological adaptations such as these are complemented by hydrolytic enzymes secreted into the environment to digest large organic molecules—such as polysaccharides, proteins, lipids, and other organic substrates—into smaller molecules that may then be absorbed as nutrients.[53][54][55] The vast majority of filamentous fungi grow in a polar fashion—i.e., by extension into one direction—by elongation at the tip (apex) of the hypha.[56] Alternative forms of fungal growth include intercalary extension (i.e., by longitudinal expansion of hyphal compartments that are below the apex) as in the case of some endophytic fungi,[57] or growth by volume expansion during the development of mushroom stipes and other large organs.[58] Growth of fungi as multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants[59]—has several functions, including the development of fruiting bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication.[60]

Traditionally, the fungi are considered heterotrophs, organisms that rely solely on carbon fixed by other organisms for metabolism. Fungi have evolved a high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate, ammonia, acetate, or ethanol.[61][62] For some species it has been shown that the pigment melanin may play a role in extracting energy from ionizing radiation, such as gamma radiation; however, this form of "radiotrophic" growth has only been described for a few species, the effects on growth rates are small, and the underlying biophysical and biochemical processes are not known.[28] The authors speculate that this process might bear similarity to CO2 fixation via visible light, but instead utilizing ionizing radiation as a source of energy.[63]

Reproduction

Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this kingdom of organisms.[64] It is estimated that a third of all fungi reproduce by different modes of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph and the anamorph.[65] Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules.

Asexual reproduction

Asexual reproduction via vegetative spores (conidia) or through mycelial fragmentation is common; it maintains clonal populations adapted to a specific niche, and allows more rapid dispersal than sexual reproduction.[66] The "Fungi imperfecti" (fungi lacking the perfect or sexual stage) or Deuteromycota comprise all the species which lack an observable sexual cycle.[67]

Sexual reproduction

Sexual reproduction with meiosis exists in all fungal phyla (with the exception of the Glomeromycota).[68] It differs in many aspects from sexual reproduction in animals or plants. Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies.[69][70] Mating experiments between fungal isolates may identify species on the basis of biological species concepts.[70] The major fungal groupings have initially been delineated based on the morphology of their sexual structures and spores; for example, the spore-containing structures, asci and basidia, can be used in the identification of ascomycetes and basidiomycetes, respectively. Some species may allow mating only between individuals of opposite mating type, while others can mate and sexually reproduce with any other individual or itself. Species of the former mating system are called heterothallic, and of the latter homothallic.[71]

Most fungi have both an haploid and diploid stage in their life cycles. In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosis, is required for the initiation of the sexual cycle. Ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells (see heterokaryosis).[72]

Microscopic view of numerous translucent or transparent elongated sac-like structures each containing eight spheres lined up in a row
The 8-spored asci of Morchella elata, viewed with phase contrast microscopy

In ascomycetes, dikaryotic hyphae of the hymenium (the spore-bearing tissue layer) form a characteristic hook at the hyphal septum. During cell division, formation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. An ascus (plural asci) is then formed, in which karyogamy (nuclear fusion) occurs. Asci are embedded in an ascocarp, or fruiting body. Karyogamy in the asci is followed immediately by meiosis and the production of ascospores. After dispersal, the ascospores may germinate and form a new haploid mycelium.[73]

Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Compatible haploid hyphae fuse to produce a dikaryotic mycelium. However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. A specialized anatomical structure, called a clamp connection, is formed at each hyphal septum. As with the structurally similar hook in the ascomycetes, the clamp connection in the basidiomycetes is required for controlled transfer of nuclei during cell division, to maintain the dikaryotic stage with two genetically different nuclei in each hyphal compartment.[74] A basidiocarp is formed in which club-like structures known as basidia generate haploid basidiospores after karyogamy and meiosis.[75] The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology section).

In glomeromycetes (formerly zygomycetes), haploid hyphae of two individuals fuse, forming a gametangium, a specialized cell structure that becomes a fertile gamete-producing cell. The gametangium develops into a zygospore, a thick-walled spore formed by the union of gametes. When the zygospore germinates, it undergoes meiosis, generating new haploid hyphae, which may then form asexual sporangiospores. These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia.[76]

Spore dispersal

Both asexual and sexual spores or sporangiospores are often actively dispersed by forcible ejection from their reproductive structures. This ejection ensures exit of the spores from the reproductive structures as well as travelling through the air over long distances.

A brown, cup-shaped fungus with several greyish disc-shaped structures lying within
The bird's nest fungus Cyathus stercoreus

Specialized mechanical and physiological mechanisms, as well as spore surface structures (such as hydrophobins), enable efficient spore ejection.[77] For example, the structure of the spore-bearing cells in some ascomycete species is such that the buildup of substances affecting cell volume and fluid balance enables the explosive discharge of spores into the air.[78] The forcible discharge of single spores termed ballistospores involves formation of a small drop of water (Buller's drop), which upon contact with the spore leads to its projectile release with an initial acceleration of more than 10,000 g;[79] the net result is that the spore is ejected 0.01–0.02 cm, sufficient distance for it to fall through the gills or pores into the air below.[80] Other fungi, like the puffballs, rely on alternative mechanisms for spore release, such as external mechanical forces. The bird's nest fungi use the force of falling water drops to liberate the spores from cup-shaped fruiting bodies.[81] Another strategy is seen in the stinkhorns, a group of fungi with lively colors and putrid odor that attract insects to disperse their spores.[82]

Other sexual processes

Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera Penicillium and Aspergillus, may exchange genetic material via parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells.[83] The frequency and relative importance of parasexual events is unclear and may be lower than other sexual processes. It is known to play a role in intraspecific hybridization[84] and is likely required for hybridization between species, which has been associated with major events in fungal evolution.[85]

Evolution

In contrast to plants and animals, the early fossil record of the fungi is meager. Factors that likely contribute to the under-representation of fungal species among fossils include the nature of fungal fruiting bodies, which are soft, fleshy, and easily degradable tissues and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resemble extant fungi.[86] Often recovered from a permineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined with light microscopy or transmission electron microscopy.[87] Compression fossils are studied by dissolving the surrounding matrix with acid and then using light or scanning electron microscopy to examine surface details.[88]

The earliest fossils possessing features typical of fungi date to the Proterozoic eon, some 1,430 million years ago (Ma); these multicellular benthic organisms had filamentous structures with septa, and were capable of anastomosis.[89] More recent studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on the basis of comparisons of the rate of evolution in closely related groups.[90] For much of the Paleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extant Chytrids in having flagellum-bearing spores.[91] The evolutionary adaptation from an aquatic to a terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, including parasitism, saprobism, and the development of mutualistic relationships such as mycorrhiza and lichenization.[92] Recent (2009) studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times.[93]

The fungi probably colonized the land during the Cambrian (542–488.3 Ma), long before land plants.[94] Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460 Ma) resemble modern-day Glomerales, and existed at a time when the land flora likely consisted of only non-vascular bryophyte-like plants.[95] Prototaxites, which was probably a fungus or lichen, would have been the tallest organism of the late Silurian. Fungal fossils do not become common and uncontroversial until the early Devonian (416–359.2 Ma), when they are abundant in the Rhynie chert, mostly as Zygomycota and Chytridiomycota.[94][96][97] At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged,[98] and all modern classes of fungi were present by the Late Carboniferous (Pennsylvanian, 318.1–299 Ma).[99]

Lichen-like fossils have been found in the Doushantuo Formation in southern China dating back to 635–551 Ma.[100] Lichens were a component of the early terrestrial ecosystems, and the estimated age of the oldest terrestrial lichen fossil is 400 Ma;[101] this date corresponds to the age of the oldest known sporocarp fossil, a Paleopyrenomycites species found in the Rhynie Chert.[102] The oldest fossil with microscopic features resembling modern-day basidiomycetes is Palaeoancistrus, found permineralized with a fern from the Pennsylvanian.[103] Rare in the fossil record are the homobasidiomycetes (a taxon roughly equivalent to the mushroom-producing species of the agaricomycetes). Two amber-preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct species Archaeomarasmius legletti) appeared during the mid-Cretaceous, 90 Ma.[104][105]

Some time after the Permian-Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments) formed, suggesting that fungi were the dominant life form at this time, representing nearly 100% of the available fossil record for this period.[106] However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess,[107] the spike did not appear worldwide,[108][109 ] and in many places it did not fall on the Permian-Triassic boundary.[110]

Taxonomy

Even though traditionally included in many botany curricula and textbooks, fungi are now thought to be more closely related to animals than to plants and are placed with the animals in the monophyletic group of opisthokonts.[111] Analyses using molecular phylogenetics support a monophyletic origin of the Fungi.[37] The taxonomy of the Fungi is in a state of constant flux, especially due to recent research based on DNA comparisons. These current phylogenetic analyses often overturn classifications based on older and sometimes less discriminative methods based on morphological features and biological species concepts obtained from experimental matings.[112]

There is no unique generally accepted system at the higher taxonomic levels and there are frequent name changes at every level, from species upwards. Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent nomenclature.[37][113] Fungal species can also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction. Web sites such as Index Fungorum and ITIS list current names of fungal species (with cross-references to older synonyms).

The 2007 classification of Kingdom Fungi is the result of a large-scale collaborative research effort involving dozens of mycologists and other scientists working on fungal taxonomy.[37] It recognizes seven phyla, two of which—the Ascomycota and the Basidiomycota—are contained within a branch representing subkingdom Dikarya. The below cladogram depicts the major fungal taxa and their relationship to opisthokont and unikont organisms. The lengths of the branches in this tree are not proportional to evolutionary distances.

Taxonomic groups

The major phyla (sometimes called divisions) of fungi have been classified mainly on the basis of characteristics of their sexual reproductive structures. Currently, seven phyla are proposed: Microsporidia, Chytridiomycota, Blastocladiomycota, Neocallimastigomycota, Glomeromycota, Ascomycota, and Basidiomycota.[37]

Microscopic view of a layer of translucent grayish-colored cells, some containing small darkly colored spheres
Arbuscular mycorrhiza seen under microscope. Flax root cortical cells containing paired arbuscules.

Phylogenetic analysis has demonstrated that the Microsporidia, unicellular parasites of animals and protists, are fairly recent and highly derived endobiotic fungi (living within the tissue of another species).[91][114] One 2006 study concludes that the Microsporidia are a sister group to the true fungi, that is, they are each other's closest evolutionary relative.[115] Hibbett and colleagues suggest that this analysis does not clash with their classification of the Fungi, and although the Microsporidia are elevated to phylum status, it is acknowledged that further analysis is required to clarify evolutionary relationships within this group.[37]

The Chytridiomycota are commonly known as chytrids. These fungi are distributed worldwide. Chytrids produce zoospores that are capable of active movement through aqueous phases with a single flagellum, leading early taxonomists to classify them as protists. Molecular phylogenies, inferred from rRNA sequences in ribosomes, suggest that the Chytrids are a basal group divergent from the other fungal phyla, consisting of four major clades with suggestive evidence for paraphyly or possibly polyphyly.[91]

The Blastocladiomycota were previously considered a taxonomic clade within the Chytridiomycota. Recent molecular data and ultrastructural characteristics, however, place the Blastocladiomycota as a sister clade to the Zygomycota, Glomeromycota, and Dikarya (Ascomycota and Basiomycota). The blastocladiomycetes are saprotrophs, feeding on decomposing organic matter, and they are parasites of all eukaryotic groups. Unlike their close relatives, the chytrids, which mostly exhibit zygotic meiosis, the blastocladiomycetes undergo sporic meiosis.[91]

The Neocallimastigomycota were earlier placed in the phylum Chytridomycota. Members of this small phylum are anaerobic organisms, living in the digestive system of larger herbivorous mammals and possibly in other terrestrial and aquatic environments. They lack mitochondria but contain hydrogenosomes of mitochondrial origin. As the related chrytrids, neocallimastigomycetes form zoospores that are posteriorly uniflagellate or polyflagellate.[37]

Members of the Glomeromycota form arbuscular mycorrhizae, a form of symbiosis where fungal hyphae invade plant root cells and both species benefit from the resulting increased supply of nutrients. All known Glomeromycota species reproduce asexually.[68] The symbiotic association between the Glomeromycota and plants is ancient, with evidence dating to 400 million years ago.[116] Formerly part of the Zygomycota (commonly known as 'sugar' and 'pin' molds), the Glomeromycota were elevated to phylum status in 2001 and now replace the older phylum Zygomycota.[117] Fungi that were placed in the Zygomycota are now being reassigned to the Glomeromycota, or the subphyla incertae sedis Mucoromycotina, Kickxellomycotina, the Zoopagomycotina and the Entomophthoromycotina.[37] Some well-known examples of fungi formerly in the Zygomycota include black bread mold (Rhizopus stolonifer), and Pilobolus species, capable of ejecting spores several meters through the air.[118] Medically relevant genera include Mucor, Rhizomucor, and Rhizopus.

Cross-section of a cup-shaped structure showing locations of developing meiotic asci (upper edge of cup, left side, arrows pointing to two gray-colored cells containing four and two small circles), sterile hyphae (upper edge of cup, right side, arrows pointing to white-colored cells with a single small circle in them), and mature asci (upper edge of cup, pointing to two gray-colored cells with eight small circles in them)
Diagram of an apothecium (the typical cup-like reproductive structure of Ascomycetes) showing sterile tissues as well as developing and mature asci.

The Ascomycota, commonly known as sac fungi or ascomycetes, constitute the largest taxonomic group within the Eumycota.[36] These fungi form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This phylum includes morels, a few mushrooms and truffles, single-celled yeasts (e.g., of the genera Saccharomyces, Kluyveromyces, Pichia, and Candida), and many filamentous fungi living as saprotrophs, parasites, and mutualistic symbionts. Prominent and important genera of filamentous ascomycetes include Aspergillus, Penicillium, Fusarium, and Claviceps. Many ascomycete species have only been observed undergoing asexual reproduction (called anamorphic species), but analysis of molecular data has often been able to identify their closest teleomorphs in the Ascomycota.[119] Because the products of meiosis are retained within the sac-like ascus, ascomycetes have been used for elucidating principles of genetics and heredity (e.g. Neurospora crassa).[120]

Members of the Basidiomycota, commonly known as the club fungi or basidiomycetes, produce meiospores called basidiospores on club-like stalks called basidia. Most common mushrooms belong to this group, as well as rust and smut fungi, which are major pathogens of grains. Other important basidiomycetes include the maize pathogen Ustilago maydis,[121] human commensal species of the genus Malassezia,[122] and the opportunistic human pathogen, Cryptococcus neoformans.[123]

Fungus-like organisms

Because of similarities in morphology and lifestyle, the slime molds (myxomycetes) and water molds (oomycetes) were formerly classified in the kingdom Fungi. Unlike true fungi the cell walls of these organisms contain cellulose and lack chitin. Slime molds are unikonts like fungi, but are grouped in the Amoebozoa. Water molds are diploid bikonts, grouped in the Chromalveolate kingdom. Neither water molds nor slime molds are closely related to the true fungi, and, therefore, taxonomists no longer group them in the kingdom Fungi. Nonetheless, studies of the oomycetes and myxomycetes are still often included in mycology textbooks and primary research literature.[124]

The nucleariids, currently grouped in the Choanozoa, may be a sister group to the eumycete clade, and as such could be included in an expanded fungal kingdom.[125]

Ecology

Although often inconspicuous, fungi occur in every environment on Earth and play very important roles in most ecosystems. Along with bacteria, fungi are the major decomposers in most terrestrial (and some aquatic) ecosystems, and therefore play a critical role in biogeochemical cycles[126] and in many food webs. As decomposers, they play an essential role in nutrient cycling, especially as saprotrophs and symbionts, degrading organic matter to inorganic molecules, which can then re-enter anabolic metabolic pathways in plants or other organisms.[127][128]

Symbiosis

Many fungi have important symbiotic relationships with organisms from most if not all Kingdoms.[129][130][131] These interactions can be mutualistic or antagonistic in nature, or in the case of commensal fungi are of no apparent benefit or detriment to the host.[132][133][134]

With plants

Mycorrhizal symbiosis between plants and fungi is one of the most well-known plant – fungus associations and is of significant importance for plant growth and persistence in many ecosystems; over 90% of all plant species engage in mycorrhizal relationships with fungi and are dependent upon this relationship for survival.[135]

A microscopic view of blue-stained cells, some with dark wavy lines in them
The dark filaments are hyphae of the endophytic fungus Neotyphodium coenophialum in the intercellular spaces of tall fescue leaf sheath tissue

The mycorrhizal symbiosis is ancient, dating to at least 400 million years ago.[116] It often increases the plant's uptake of inorganic compounds, such as nitrate and phosphate from soils having low concentrations of these key plant nutrients.[127][136] The fungal partners may also mediate plant-to-plant transfer of carbohydrates and other nutrients. Such mycorrhizal communities are called "common mycorrhizal networks".[137] A special case of mycorrhiza is myco-heterotrophy, whereby the plant parasitizes the fungus, obtaining all of its nutrients from its fungal symbiont.[138] Some fungal species inhabit the tissues inside roots, stems, and leaves, in which case they are called endophytes.[139] Similar to mycorrhiza, endophytic colonization by fungi may benefit both symbionts; for example, endophytes of grasses impart to their host increased resistance to herbivores and other environmental stresses and receive food and shelter from the plant in return.[140]

With algae and cyanobacteria

A green, leaf-like structure attached to a tree, with a pattern of ridges and depression on the bottom surface
The lichen Lobaria pulmonaria, a symbiosis of fungal, algal, and cyanobacterial species.

Lichens are formed by a symbiotic relationship between algae or cyanobacteria (referred to in lichen terminology as "photobionts") and fungi (mostly various species of ascomycetes and a few basidiomycetes), in which individual photobiont cells are embedded in a tissue formed by the fungus.[141] Lichens occur in every ecosystem on all continents, play a key role in soil formation and the initiation of biological succession,[142] and are the dominating life forms in extreme environments, including polar, alpine, and semiarid desert regions.[143] They are able to grow on inhospitable surfaces, including bare soil, rocks, tree bark, wood, shells, barnacles and leaves.[144] As in mycorrhizas, the photobiont provides sugars and other carbohydrates via photosynthesis, while the fungus provides minerals and water. The functions of both symbiotic organisms are so closely intertwined that they function almost as a single organism; in most cases the resulting organism differs greatly from the individual components. Lichenization is a common mode of nutrition; around 20% of fungi—between 17,500 and 20,000 described species—are lichenized.[145] Characteristics common to most lichens include obtaining organic carbon by photosynthesis, slow growth, small size, long life, long-lasting (seasonal) vegetative reproductive structures, mineral nutrition obtained largely from airborne sources, and greater tolerance of dessication than most other photosynthetic organisms in the same habitat.[146]

With insects

Many insects also engage in mutualistic relationships with fungi. Several groups of ants cultivate fungi in the order Agaricales as their primary food source, while ambrosia beetles cultivate various species of fungi in the bark of trees that they infest.[147] Similarly, females of several wood wasp species (genus Sirex) inject their eggs together with spores of the wood-rotting fungus Amylostereum areolatum into the sapwood of pine trees; the growth of the fungus provides ideal nutritional conditions for the development of the wasp larvae.[148] Termites on the African savannah are also known to cultivate fungi,[149] and yeasts of the genera Candida and Lachancea inhabit the gut of a wide range of insects, including neuropterans, beetles, and cockroaches; it is not known whether these fungi benefit their hosts.[150]

As pathogens and parasites

A thin brown stick positioned horizontally with roughly two dozen clustered orange-red leaves originating from a single point in the middle of the stick. These orange leaves are three to four times larger than the few other green leaves growing out of the stick, and are covered on the lower leaf surface with hundreds of tiny bumps. The background shows the green leaves and branches of neighboring shrubs.
The plant pathogen Aecidium magellanicum causes calafate rust, seen here on a Berberis shrub in Chile.

Many fungi are parasites on plants, animals (including humans), and other fungi. Serious pathogens of many cultivated plants causing extensive damage and losses to agriculture and forestry include the rice blast fungus Magnaporthe oryzae,[151] tree pathogens such as Ophiostoma ulmi and Ophiostoma novo-ulmi causing Dutch elm disease,[152] and Cryphonectria parasitica responsible for chestnut blight,[153] and plant pathogens in the genera Fusarium, Ustilago, Alternaria, and Cochliobolus.[133] Some carnivorous fungi, like Paecilomyces lilacinus, are predators of nematodes, which they capture using an array of specialized structures such as constricting rings or adhesive nets.[154]

Some fungi can cause serious diseases in humans, several of which may be fatal if untreated. These include aspergilloses, candidoses, coccidioidomycosis, cryptococcosis, histoplasmosis, mycetomas, and paracoccidioidomycosis. Furthermore, persons with immuno-deficiencies are particularly susceptible to disease by genera such as Aspergillus, Candida, Cryptoccocus,[134][155][156] Histoplasma,[157] and Pneumocystis.[158] Other fungi can attack eyes, nails, hair, and especially skin, the so-called dermatophytic and keratinophilic fungi, and cause local infections such as ringworm and athlete’s foot.[159] Fungal spores are also a cause of allergies, and fungi from different taxonomic groups can evoke allergic reactions.[160]

Human use

The human use of fungi for food preparation or preservation and other purposes is extensive and has a long history. Mushroom farming and mushroom gathering are large industries in many countries. The study of the historical uses and sociological impact of fungi is known as ethnomycology. Because of the capacity of this group to produce an enormous range of natural products with antimicrobial or other biological activities, many species have long been used or are being developed for industrial production of antibiotics, vitamins, and anti-cancer and cholesterol-lowering drugs. More recently, methods have been developed for genetic engineering of fungi,[161] enabling metabolic engineering of fungal species. For example, genetic modification of yeast species[162 ]—which are easy to grow at fast rates in large fermentation vessels—has opened up ways of pharmaceutical production that are potentially more efficient than production by the original source organisms.[163]

Antibiotics

Many species produce metabolites that are major sources of pharmacologically active drugs. Particularly important are the antibiotics, including the penicillins, a structurally related group of β-lactam antibiotics that are synthesized from small peptides. Although naturally occurring penicillins such as penicillin G (produced by Penicillium chrysogenum) have a relatively narrow spectrum of biological activity, a wide range of other penicillins can be produced by chemical modification of the natural penicillins. Modern penicillins are semisynthetic compounds, obtained initially from fermentation cultures, but then structurally altered for specific desirable properties.[164] Other antibiotics produced by fungi include: griseofulvin from Penicillium griseofulvin used to treat dermatophyte infections of the skin, hair and nails;[165] ciclosporin, commonly used as an immunosuppressant during transplant surgery; and fusidic acid, used to help control infection from methicillin-resistant Staphylococcus aureus bacteria.[166] Widespread use of these antibiotics for the treatment of bacterial diseases, such as tuberculosis, syphilis, leprosy, and many others began in the early 20th century and continues to play a major part in anti-bacterial chemotherapy. In nature, antibiotics of fungal or bacterial origin appear to play a dual role: at high concentrations they act as chemical defense against competition with other microorganisms in species-rich environments, such as the rhizosphere, and at low concentrations as quorum-sensing molecules for intra- or interspecies signaling.[167 ]

Cultured foods

Baker's yeast or Saccharomyces cerevisiae, a single-celled fungus, is used to make bread and other wheat-based products, such as pizza dough and dumplings.[168] Yeast species of the genus Saccharomyces are also used to produce alcoholic beverages through fermentation.[169] Shoyu koji mold (Aspergillus oryzae) is an essential ingredient in brewing Shoyu (soy sauce) and sake, and the preparation of miso,[170] while Rhizopus species are used for making tempeh.[171 ] Several of these fungi are domesticated species that were bred or selected according to their capacity to ferment food without producing harmful mycotoxins (see below), which are produced by very closely related Aspergilli.[172] Quorn, a meat substitute, is made from Fusarium venenatum.[173]

Medicinal use

 Upper surface view of a kidney-shaped fungus, brownish-red with a lighter yellow-brown margin, and a somewhat varnished or shiny appearance. Two dried yellow-orange caterpillars, one with a curly grayish-colored fungus growing out of one of its ends. The grayish fungus is roughly equal to or slightly greater in length than the caterpillar, and tapers in thickness to a narrow end.
The medicinal fungi Ganoderma lucidum (left) and Cordyceps sinensis (right).

Certain mushrooms enjoy usage as therapeutics in folk medicines, such as Traditional Chinese medicine. Notable medicinal mushrooms with a well-documented history of use include Agaricus blazei,[174][175] Ganoderma lucidum,[176] and Cordyceps sinensis.[177] Research has identified compounds produced by these and other fungi that have inhibitory biological effects against viruses[178][179] and cancer cells.[174][180] Specific metabolites, such as polysaccharide-K, ergotamine, and β-lactam antibiotics, are routinely used in clinical medicine. The shiitake mushroom is a source of lentinan, a clinical drug approved for use in cancer treatments in several countries, including Japan.[181][182] In Europe and Japan, polysaccharide-K (brand name Krestin), a chemical derived from Trametes versicolor, is an approved adjuvant for cancer therapy.[183]

Edible and poisonous species

Two light yellow-green mushrooms with stems and caps, one smaller and still in the ground, the larger one pulled out and laid beside the other to show its bulbous stem with a ring
Amanita phalloides accounts for the majority of fatal mushroom poisonings worldwide.

Edible mushrooms are well-known examples of fungi. Many are commercially raised, but others must be harvested from the wild. Agaricus bisporus, sold as button mushrooms when small or Portobello mushrooms when larger, is a commonly eaten species, used in salads, soups, and many other dishes. Many Asian fungi are commercially grown and have increased in popularity in the West. They are often available fresh in grocery stores and markets, including straw mushrooms (Volvariella volvacea), oyster mushrooms (Pleurotus ostreatus), shiitakes (Lentinula edodes), and enokitake (Flammulina spp.).[184]

There are many more mushroom species that are harvested from the wild for personal consumption or commercial sale. Milk mushrooms, morels, chanterelles, truffles, black trumpets, and porcini mushrooms (Boletus edulis) (also known as king boletes) demand a high price on the market. They are often used in gourmet dishes.[185]

Certain types of cheeses require inoculation of milk curds with fungal species that impart a unique flavor and texture to the cheese. Examples include the blue color in cheeses such as Stilton or Roquefort, which are made by inoculation with Penicillium roqueforti.[186] Molds used in cheese production are non-toxic and are thus safe for human consumption; however, mycotoxins (e.g., aflatoxins, roquefortine C, patulin, or others) may accumulate because of growth of other fungi during cheese ripening or storage.[187]

Many mushroom species are poisonous to humans, with toxicities ranging from slight digestive problems or allergic reactions as well as hallucinations to severe organ failures and death. Genera with mushrooms containing deadly toxins include Conocybe, Galerina, Lepiota, and most infamously, Amanita.[188] The latter genus includes the destroying angel (A. virosa) and the death cap (A. phalloides), the most common cause of deadly mushroom poisoning.[189] The false morel (Gyromitra esculenta) is occasionally considered a delicacy when cooked, yet can be highly toxic when eaten raw.[190] Tricholoma equestre was considered edible until being implicated in serious poisonings causing rhabdomyolysis.[191 ] Fly agaric mushrooms (Amanita muscaria) also cause occasional non-fatal poisonings, mostly as a result of ingestion for use as a recreational drug for its hallucinogenic properties. Historically, fly agaric was used by different peoples in Europe and Asia and its present usage for religious or shamanic purposes is reported from some ethnic groups such as the Koryak people of north-eastern Siberia.[192 ]

As it is difficult to accurately identify a safe mushroom without proper training and knowledge, it is often advised to assume that a wild mushroom is poisonous and not to consume it.[193][194]

Pest control

Two dead grasshoppers with a whitish fuzz growing on them
Grasshoppers killed by Beauveria bassiana

In agriculture, fungi may be useful if they actively compete for nutrients and space with pathogenic microorganisms such as bacteria or other fungi via the competitive exclusion principle,[195 ] or if they are parasites of these pathogens. For example, certain species may be used to eliminate or suppress the growth of harmful plant pathogens, such as insects, mites, weeds, nematodes and other fungi that cause diseases of important crop plants. [196] This has generated strong interest in practical applications that use these fungi in the biological control of these agricultural pests. Entomopathogenic fungi can be used as biopesticides, as they actively kill insects.[197 ] Examples that have been used as biological insecticides are Beauveria bassiana, Metarhizium anisopliae, Hirsutella spp, Paecilomyces spp, and Verticillium lecanii.[198][199] Endophytic fungi of grasses of the genus Neotyphodium, such as N. coenophialum, produce alkaloids that are toxic to a range of invertebrate and vertebrate herbivores. These alkaloids protect grass plants from herbivory, but several endophyte alkaloids can poison grazing animals, such as cattle and sheep.[200] Infecting cultivars of pasture or forage grasses with Neotyphodium endophytes is one approach being used in grass breeding programs; the fungal strains are selected for producing only alkaloids that increase resistance to herbivores such as insects, while being non-toxic to livestock.[201]

Bioremediation

Certain fungi, in particular "white rot" fungi, can degrade insecticides, herbicides, pentachlorophenol, creosote, coal tars, and heavy fuels and turn them into carbon dioxide, water, and basic elements.[202] Fungi have been shown to biomineralize uranium oxides, suggesting they may have application in the bioremediation of radioactively polluted sites.[203][204][205]

Model organisms

Several pivotal discoveries in biology were made by researchers using fungi as model organisms, that is, fungi that grow and sexually reproduce rapidly in the laboratory. For example, the one gene-one enzyme hypothesis was formulated by scientists who used the bread mold Neurospora crassa to test their biochemical theories.[206] Other important model fungi are Aspergillus nidulans and the yeasts, Saccaromyces cerevisiae and Schizosaccharomyces pombe, each of which has a long history of use to investigate issues in eukaryotic cell biology and genetics, such as cell cycle regulation, chromatin structure, and gene regulation. Other fungal models have more recently emerged that each address specific biological questions relevant to medicine, plant pathology, and industrial uses; examples include Candida albicans, a dimorphic, opportunistic human pathogen,[207] Magnaporthe grisea, a plant pathogen,[208] and Pichia pastoris, a yeast widely used for eukaryotic protein expression.[209]

Others

Fungi are used extensively to produce industrial chemicals like citric, gluconic, lactic, and malic acids,[210] antibiotics, and even to make stonewashed jeans.[211] Fungi are also sources of industrial enzymes, such as lipases used in biological detergents,[212] amylases,[213] cellulases,[214] invertases, proteases and xylanases.[215] Several species, most notably Psilocybin mushrooms (colloquially known as magic mushrooms), are ingested for their psychedelic properties, both recreationally and religiously.

Mycotoxins

(6aR,9R)-N-((2R,5S,10aS,10bS)-5-benzyl-10b-hydroxy-2-methyl-3,6-dioxooctahydro-2H-oxazolo[3,2-a] pyrrolo[2,1-c]pyrazin-2-yl)-7-methyl-4,6,6a,7,8,9-hexahydroindolo[4,3-fg] quinoline-9-carboxamide
Ergotamine, a major mycotoxin produced by Claviceps species, which if ingested can cause gangrene, convulsions, and hallucinations

Many fungi produce biologically active compounds, several of which are toxic to animals or plants and are therefore called mycotoxins. Of particular relevance to humans are mycotoxins produced by molds causing food spoilage, and poisonous mushrooms (see above). Particularly infamous are the lethal amatoxins in some Amanita mushrooms, and ergot alkaloids, which have a long history of causing serious epidemics of ergotism (St Anthony's Fire) in people consuming rye or related cereals contaminated with sclerotia of the ergot fungus, Claviceps purpurea.[216] Other notable mycotoxins include the aflatoxins, which are insidious liver toxins and highly carcinogenic metabolites produced by certain Aspergillus species often growing in or on grains and nuts consumed by humans, ochratoxins, patulin, and trichothecenes (e.g., T-2 mycotoxin) and fumonisins, which have significant impact on human food supplies or animal livestock.[217]

Mycotoxins are secondary metabolites (or natural products), and research has established the existence of biochemical pathways solely for the purpose of producing mycotoxins and other natural products in fungi.[218 ] Mycotoxins may provide fitness benefits in terms of physiological adaptation, competition with other microbes and fungi, and protection from consumption (fungivory).[219][220]

Mycology

Mycology is the branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, and psychotropic substances consumed for religious purposes, as well as their dangers, such as poisoning or infection. The field of phytopathology, the study of plant diseases, is closely related because many plant pathogens are fungi.[221]

Use of fungi by humans dates back to prehistory; Ötzi the Iceman, a well-preserved mummy of a 5,300 year old Neolithic man found frozen in the Austrian Alps, carried two species of polypore mushrooms that may have been used as tinder (Fomes fomentarius), or for medicinal purposes (Piptoporus betulinus).[222] Ancient peoples have used fungi as food sources – often unknowingly – for millennia, in the preparation of leavened bread and fermented juices. Some of the oldest written records contain references to the destruction of crops that were probably caused by pathogenic fungi.[223]

History

Mycology is a relatively new science that became systematic after the development of the microscope in the 16th century. Although fungal spores were first observed by Giambattista della Porta in 1588, the seminal work in the development of mycology is considered to be the publication of Pier Antonio Micheli's 1729 work Nova plantarum genera.[224] Micheli not only observed spores, but showed that under the proper conditions, they could be induced into growing into the same species of fungi from which they originated.[225] Extending the use of the binomial system of nomenclature introduced by Carl Linnaeus in his Species plantarum (1753), the Dutch Christian Hendrik Persoon (1761–1836) established the first classification of mushrooms with such skill so as to be considered a founder of modern mycology. Later, Elias Magnus Fries (1794–1878) further elaborated the classification of fungi, using spore color and various microscopic characteristics, methods still used by taxonomists today. Other notable early contributors to mycology in the 17th–19th and early 20th centuries include Miles Joseph Berkeley, August Carl Joseph Corda, Anton de Bary, the brothers Louis René and Charles Tulasne, Arthur H. R. Buller, Curtis G. Lloyd, and Pier Andrea Saccardo. The 20th century has seen a modernization of mycology that has come from advances in biochemistry, genetics, molecular biology, and biotechnology. The use of DNA sequencing technologies and phylogenetic analysis has provided new insights into fungal relationships and biodiversity, and has challenged traditional morphology-based groupings in fungal taxonomy.[226]

See also

Footnotes

  1. ^ Moore RT. (1980). "Taxonomic proposals for the classification of marine yeasts and other yeast-like fungi including the smuts". Botanica Marine 23: 361–73.  
  2. ^ The classification system presented here is based on the 2007 phylogenetic study by Hibbett et al.
  3. ^ Simpson DP. (1979). Cassell's Latin Dictionary (5 ed.). London: Cassell Ltd. p. 883. ISBN 0-304-52257-0.  
  4. ^ a b Ainsworth, p. 2.
  5. ^ Alexopoulos et al., p. 1.
  6. ^ Bruns T. (2006). "Evolutionary biology: a kingdom revised". Nature 443 (7113): 758–61. doi:10.1038/443758a. PMID 17051197.  
  7. ^ Baldauf; Palmer, JD (1993). "Animals and fungi are each other's closest relatives: congruent evidence from multiple proteins". Proceedings of the National Academy of Sciences of the United States of America 90 (24): 11558–62. doi:10.1073/pnas.90.24.11558. PMID 8265589.   edit
  8. ^ Deacon, p. 4.
  9. ^ a b Deacon, pp. 128–29.
  10. ^ Alexopoulos et al., pp. 28–33.
  11. ^ Alexopoulos et al., pp. 31–32.
  12. ^ Shoji JY, Arioka M, Kitamoto K. (2006). "Possible involvement of pleiomorphic vacuolar networks in nutrient recycling in filamentous fungi". Autophagy 2 (3): 226–27. PMID 16874107.  
  13. ^ Deacon, p. 58.
  14. ^ Zabriskie TM, Jackson MD. (2000). "Lysine biosynthesis and metabolism in fungi". Natural Product Reports 17 (1): 85–97. doi:10.1039/a801345d. PMID 10714900.  
  15. ^ Xu H, Andi B, Qian J, West AH, Cook PF. (2006). "The α-aminoadipate pathway for lysine biosynthesis in fungi". Cellular Biochemistry and Biophysics 46 (1): 43–64. doi:10.1385/CBB:46:1:43. PMID 16943623.  
  16. ^ Alexopoulos et al., pp. 27–28.
  17. ^ Alexopoulos et al., p. 685.
  18. ^ Desjardin DE, Oliveira AG, Stevani CV. (2008). "Fungi bioluminescence revisited". Photochemical & Photobiological Sciences 7 (2): 170–82. doi:10.1039/b713328f. PMID 18264584.  
  19. ^ a b Alexopoulos et al., p. 30.
  20. ^ Alexopoulos et al., pp. 32–33.
  21. ^ Bowman SM, Free SJ. (2006). "The structure and synthesis of the fungal cell wall". Bioessays 28 (8): 799–808. doi:10.1002/bies.20441. PMID 16927300.  
  22. ^ Alexopoulos et al., p. 33.
  23. ^ Mihail JD, Bruhn JN. (2005). "Foraging behaviour of Armillaria rhizomorph systems". Mycological Research 109 (Pt 11): 1195–207. doi:10.1017/S0953756205003606. PMID 16279413.  
  24. ^ a b c Keller NP, Turner G, Bennett JW. (2005). "Fungal secondary metabolism—from biochemistry to genomics". Nature Reviews Microbiology 3 (12): 937–47. doi:10.1038/nrmicro1286. PMID 16322742.  
  25. ^ Wu S, Schalk M, Clark A, Miles RB, Coates R, Chappell J. (2007). "Redirection of cytosolic or plastidic isoprenoid precursors elevates terpene production in plants". Nature Biotechnology 24 (11): 1441–47. doi:10.1038/nbt1251. PMID 17057703.  
  26. ^ Tudzynski B. (2005). "Gibberellin biosynthesis in fungi: genes, enzymes, evolution, and impact on biotechnology". Applied Microbiology and Biotechnology 66 (6): 597–611. doi:10.1007/s00253-004-1805-1. PMID 15578178.  
  27. ^ Vaupotic T, Veranic P, Jenoe P, Plemenitas A. (2008). "Mitochondrial mediation of environmental osmolytes discrimination during osmoadaptation in the extremely halotolerant black yeast Hortaea werneckii". Fungal Genetics and Biology 45 (6): 994–1007. doi:10.1016/j.fgb.2008.01.006. PMID 18343697.  
  28. ^ a b Dadachova E, Bryan RA, Huang X, Moadel T, Schweitzer AD, Aisen P, Nosanchuk JD, Casadevall A. (2007). "Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi". PLoS ONE 2 (5): e457. doi:10.1371/journal.pone.0000457. PMID 17520016.  
  29. ^ Raghukumar C, Raghukumar S. (1998). "Barotolerance of fungi isolated from deep-sea sediments of the Indian Ocean". Aquatic Microbial Ecology 15: 153–63. doi:10.3354/ame015153. http://hdl.handle.net/2264/1892.  
  30. ^ Sancho LG, de la Torre R, Horneck G, Ascaso C, de Los Rios A, Pintado A, Wierzchos J, Schuster M. (2007). "Lichens survive in space: results from the 2005 LICHENS experiment". Astrobiology 7 (3): 443–54. doi:10.1089/ast.2006.0046. PMID 17630840.  
  31. ^ Brem FM, Lips KR. (2008). "Batrachochytrium dendrobatidis infection patterns among Panamanian amphibian species, habitats and elevations during epizootic and enzootic stages". Diseases of Aquatic Organisms 81 (3): 189–202. doi:10.3354/dao01960. PMID 18998584.  
  32. ^ Le Calvez T, Burgaud G, Mahé S, Barbier G, Vandenkoornhuyse P. (2009). "Fungal diversity in deep sea hydrothermal ecosystems". Applied and Environmental Microbiology 75 (20): 6415–21. doi:10.1128/AEM.00653-09. PMID 19633124.  
  33. ^ This estimation is determined by combining the species count for each phyla, based on values obtained from the 10th edition of the Dictionary of the Fungi (Kirk et al., 2008): Ascomycota, 64163 species (p. 55); Basidiomycota, 31515 (p. 78); Blastocladiomycota, 179 (p. 94); Chytridiomycota, 706 (p. 142); Glomeromycota, 169 (p. 287); Microsporidia, >1300 (p. 427); Neocallimastigomycota, 20 (p. 463).
  34. ^ Mueller GM, Schmit JP. (2006). "Fungal biodiversity: what do we know? What can we predict?". Biodiversity and Conservation 16: 1–5. doi:10.1007/s10531-006-9117-7.  
  35. ^ Hawksworth DL. (2006). "The fungal dimension of biodiversity: magnitude, significance, and conservation". Mycological Research 95: 641–55. doi:10.1016/S0953-7562(09)80810-1.  
  36. ^ a b Kirk et al., p. 489.
  37. ^ a b c d e f g h i Hibbett DS, et al. (2007). "A higher level phylogenetic classification of the Fungi" (PDF). Mycological Research 111 (5): 509–47. doi:10.1016/j.mycres.2007.03.004. http://www.clarku.edu/faculty/dhibbett/AFTOL/documents/AFTOL%20class%20mss%2023,%2024/AFTOL%20CLASS%20MS%20resub.pdf.  
  38. ^ Harris SD. (2008). "Branching of fungal hyphae: regulation, mechanisms and comparison with other branching systems". Mycologia 50 (6): 823–32. doi:10.3852/08-177. PMID 19202837.  
  39. ^ Deacon, p. 51.
  40. ^ Deacon, p. 57.
  41. ^ Chang S-T, Miles PG. (2004). Mushrooms: Cultivation, Nutritional Value, Medicinal Effect and Environmental Impact. CRC Press. ISBN 0849310431.  
  42. ^ Parniske M. (2008). "Arbuscular mycorrhiza: the mother of plant root endosymbioses". Nature Reviews. Microbiology 6 (10): 763–75. doi:10.1038/nrmicro1987. PMID 18794914.  
  43. ^ Steenkamp ET, Wright J, Baldauf SL. (2006). "The protistan origins of animals and fungi". Molecular Biology and Evolution 23 (1): 93–106. doi:10.1093/molbev/msj011. PMID 16151185. http://mbe.oxfordjournals.org/cgi/content/full/23/1/93.  
  44. ^ Stevens DA, Ichinomiya M, Koshi Y, Horiuchi H. (2006). "Escape of Candida from caspofungin inhibition at concentrations above the MIC (paradoxical effect) accomplished by increased cell wall chitin; evidence for β-1,6-glucan synthesis inhibition by caspofungin". Antimicrobial Agents and Chemotherapy 50 (9): 3160–61. doi:10.1128/AAC.00563-06. PMID 16940118.  
  45. ^ Hanson, pp. 127–41.
  46. ^ Ferguson BA, Dreisbach TA, Parks CG, Filip GM, Schmitt CL. (2003). "Coarse-scale population structure of pathogenic Armillaria species in a mixed-conifer forest in the Blue Mountains of northeast Oregon". Canadian Journal of Forest Research 33: 612–23. doi:10.1139/x03-065.  
  47. ^ Alexopoulos et al., pp. 204–205.
  48. ^ Moss ST. (1986). The Biology of Marine Fungi. Cambridge, UK: Cambridge University Press. p. 76. ISBN 0-521-30899-2.  
  49. ^ Peñalva MA, Arst HN. (2002). "Regulation of gene expression by ambient pH in filamentous fungi and yeasts". Microbiology and Molecular Biology Reviews 66 (3): 426–46. doi:10.1128/MMBR.66.3.426-446.2002. PMID 12208998.  
  50. ^ a b Howard RJ, Ferrari MA, Roach DH, Money NP. (1991). "Penetration of hard substrates by a fungus employing enormous turgor pressures". Proceedings of the National Academy of Sciences USA 88 (24): 11281–84. doi:10.1073/pnas.88.24.11281. PMID 1837147.  
  51. ^ Money NP. (1998). "Mechanics of invasive fungal growth and the significance of turgor in plant infection.". Molecular Genetics of Host-Specific Toxins in Plant Disease: Proceedings of the 3rd Tottori International Symposium on Host-Specific Toxins, Daisen, Tottori, Japan, August 24–29, 1997. Netherlands: Kluwer Academic Publishers. pp. 261–71. ISBN 0-7923-4981-4.  
  52. ^ Wang ZY, Jenkinson JM, Holcombe LJ, Soanes DM, Veneault-Fourrey C, Bhambra GK, Talbot NJ. (2005). "The molecular biology of appressorium turgor generation by the rice blast fungus Magnaporthe grisea". Biochemical Society Transactions 33 (Pt 2): 384–88. doi:10.1042/BST0330384. PMID 15787612.  
  53. ^ Pereira JL, Noronha EF, Miller RN, Franco OL. (2007). "Novel insights in the use of hydrolytic enzymes secreted by fungi with biotechnological potential". Letters in Applied Microbiology 44 (6): 573–81. doi:10.1111/j.1472-765X.2007.02151.x. PMID 17576216.  
  54. ^ Schaller M, Borelli C, Korting HC, Hube B. (2007). "Hydrolytic enzymes as virulence factors of Candida albicans". Mycoses 48 (6): 365–77. doi:10.1111/j.1439-0507.2005.01165.x. PMID 16262871.  
  55. ^ Farrar JF. (1985). "Carbohydrate metabolism in biotrophic plant pathogens". Microbiological Sciences 2 (10): 314–17. PMID 3939987.  
  56. ^ Fischer R, Zekert N, Takeshita N. (2008). "Polarized growth in fungi—interplay between the cytoskeleton, positional markers and membrane domains". Molecular Microbiology 68 (4): 813–26. doi:10.1111/j.1365-2958.2008.06193.x. PMID 18399939.  
  57. ^ Christensen MJ, Bennett RJ, Ansari HA, Koga H, Johnson RD, Bryan GT, Simpson WR, Koolaard JP, Nickless EM, Voisey CR. (2008). "Epichloë endophytes grow by intercalary hyphal extension in elongating grass leaves". Fungal Genetics and Biology 45 (2): 84–93. doi:10.1016/j.fgb.2007.07.013. PMID 17919950.  
  58. ^ Money NP. (2002). "Mushroom stem cells". Bioessays 24 (10): 949–52. doi:10.1002/bies.10160. PMID 12325127.  
  59. ^ Willensdorfer M. (2009). "On the evolution of differentiated multicellularity". Evolution 63 (2): 306–23. doi:10.1111/j.1558-5646.2008.00541.x. PMID 19154376.  
  60. ^ Daniels KJ, Srikantha T, Lockhart SR, Pujol C, Soll DR. (2006). "Opaque cells signal white cells to form biofilms in Candida albicans". EMBO Journal 25 (10): 2240–52. doi:10.1038/sj.emboj.7601099. PMID 16628217.  
  61. ^ Marzluf GA. (1981). "Regulation of nitrogen metabolism and gene expression in fungi". Microbiological Reviews 45 (3): 437–61. PMID 6117784.  
  62. ^ Heynes MJ. (1994). "Regulatory circuits of the amdS gene of Aspergillus nidulans". Antonie Van Leeuwenhoek 65 (3): 179–82. doi:10.1007/BF00871944. PMID 7847883.  
  63. ^ Dadachova E, Casadevall A. (2008). "Ionizing radiation: how fungi cope, adapt, and exploit with the help of melanin". Current opinion in Microbiology 11 (6): 525–31. doi:10.1016/j.mib.2008.09.013. PMID 18848901.  
  64. ^ Alexopoulos et al., pp. 48–56.
  65. ^ Kirk et al., p. 633.
  66. ^ Heitman J. (2005). "Sexual reproduction and the evolution of microbial pathogens". Current Biology 16 (17): R711–25. doi:10.1016/j.cub.2006.07.064. PMID 16950098.  
  67. ^ Alcamo IE, Pommerville J. (2004). Alcamo's Fundamentals of Microbiology. Boston: Jones and Bartlett. p. 590. ISBN 0-7637-0067-3.  
  68. ^ a b Redecker D, Raab P. (2006). "Phylogeny of the Glomeromycota (arbuscular mycorrhizal fungi): recent developments and new gene markers". Mycologia 98 (6): 885–95. doi:10.3852/mycologia.98.6.885. PMID 17486965.  
  69. ^ Guarro J, Gené J, Stchigel AM.. "Developments in fungal taxonomy". Clinical Microbiology Reviews 12 (3): 454–500. PMID 10398676. PMC 100249. http://cmr.asm.org/cgi/content/full/12/3/454.  
  70. ^ a b Taylor JW, Jacobson DJ, Kroken S, Kasuga T, Geiser DM, Hibbett DS, Fisher MC. (2000). "Phylogenetic species recognition and species concepts in fungi". Fungal Genetics and Biology 31 (1): 21–32. doi:10.1006/fgbi.2000.1228. PMID 11118132.  
  71. ^ Metzenberg RL, Glass NL. (1990). "Mating type and mating strategies in Neurospora". Bioessays 12 (2): 53–59. doi:10.1002/bies.950120202. PMID 2140508.  
  72. ^ Jennings and Lysek, pp. 107–114.
  73. ^ Deacon, p. 31.
  74. ^ Alexopoulos et al., pp. 492–93.
  75. ^ Jennings and Lysek, p. 142.
  76. ^ Deacon, pp. 21–24.
  77. ^ Linder MB, Szilvay GR, Nakari-Setälä T, Penttilä ME. (2005). "Hydrophobins: the protein-amphiphiles of filamentous fungi". FEMS Microbiology Reviews 29 (5): 877–96. doi:10.1016/j.femsre.2005.01.004. PMID 16219510.  
  78. ^ Trail F. (2007). "Fungal cannons: explosive spore discharge in the Ascomycota". FEMS Microbiology Letters 276 (1): 12–18. doi:10.1111/j.1574-6968.2007.00900.x. PMID 17784861.  
  79. ^ Pringle A, Patek SN, Fischer M, Stolze J, Money NP. (2005). "The captured launch of a ballistospore". Mycologia 97 (4): 866–71. doi:10.3852/mycologia.97.4.866. PMID 16457355.  
  80. ^ Kirk et al., p. 495.
  81. ^ Brodie HJ. (1975). The Bird's Nest Fungi. Toronto: University of Toronto Press. ISBN 0-8020-5307-6.  
  82. ^ Alexopoulos et al., p. 545.
  83. ^ Jennings and Lysek, pp. 114–15.
  84. ^ Furlaneto MC, Pizzirani-Kleiner AA. (1992). "Intraspecific hybridisation of Trichoderma pseudokoningii by anastomosis and by protoplast fusion". FEMS Microbiology Letters 69 (2): 191–95. doi:10.1111/j.1574-6968.1992.tb05150.x. PMID 1537549.  
  85. ^ Schardl CL, Craven KD. (2003). "Interspecific hybridization in plant-associated fungi and oomycetes: a review". Molecular Ecology 12 (11): 2861–73. doi:10.1046/j.1365-294X.2003.01965.x. PMID 14629368.  
  86. ^ Donoghue MJ, Cracraft J. (2004). Assembling the tree of life. Oxford (Oxfordshire): Oxford University Press. p. 187. ISBN 0-19-517234-5.  
  87. ^ Taylor and Taylor, p. 19.
  88. ^ Taylor and Taylor, pp. 7–12.
  89. ^ Butterfield NJ. (2005). "Probable Proterozoic fungi". Paleobiology 31 (1): 165–82. doi:10.1666/0094-8373(2005)031<0165:PPF>2.0.CO;2. http://paleobiol.geoscienceworld.org/cgi/content/abstract/31/1/165.  
  90. ^ Lucking R, Huhndorf S, Pfister D, Plata ER, Lumbsch H. (2009). "Fungi evolved right on track". Mycologia 101 (6): 810–822. doi:10.3852/09-016. PMID 19927746. http://www.mycologia.org/cgi/content/abstract/09-016v1.  
  91. ^ a b c d James TY, et al. (2006). "Reconstructing the early evolution of Fungi using a six-gene phylogeny". Nature 443 (7113): 818–22. doi:10.1038/nature05110. PMID 17051209.  
  92. ^ Taylor and Taylor, pp. 84–94 and 106–107.
  93. ^ Schoch CL, Sung G-H, López-Giráldez F et al. (2009). "The Ascomycota tree of life: A phylum-wide phylogeny clarifies the origin and evolution of fundamental reproductive and ecological traits". Systematic Biology 58 (2): 224–39. doi:10.1093/sysbio/syp020.  
  94. ^ a b Brundrett MC. (2002). "Coevolution of roots and mycorrhizas of land plants". New Phytologist 154 (2): 275–304. doi:10.1046/j.1469-8137.2002.00397.x.  
  95. ^ Redecker D, Kodner R, Graham LE. (2000). "Glomalean fungi from the Ordovician". Science 289 (5486): 1920–21. doi:10.1126/science.289.5486.1920. PMID 10988069.  
  96. ^ Taylor TN, Taylor EL. (1996). "The distribution and interactions of some Paleozoic fungi". Review of Palaeobotany and Palynology 95 (1–4): 83–94. doi:10.1016/S0034-6667(96)00029-2.  
  97. ^ Dotzler N, Walker C, Krings M, Hass H, Kerp H, Taylor TN, Agerer R. (2009). "Acaulosporoid glomeromycotan spores with a germination shield from the 400-million-year-old Rhynie chert". Mycological Progress 8 (1): 9–18. doi:10.1007/s11557-008-0573-1.  
  98. ^ Taylor JW, Berbee ML. (2006). "Dating divergences in the Fungal Tree of Life: review and new analyses". Mycologia 98 (6): 838–49. doi:10.3852/mycologia.98.6.838. PMID 17486961.  
  99. ^ Blackwell M, Vilgalys R, James TY, Taylor JW. (2009). "Fungi. Eumycota: mushrooms, sac fungi, yeast, molds, rusts, smuts, etc.". Tree of Life Web Project. http://tolweb.org/Fungi/2377. Retrieved 2009-04-25.  
  100. ^ Yuan X, Xiao S, Taylor TN. (2005). "Lichen-like symbiosis 600 million years ago". Science (New York, N.Y.) 308 (5724): 1017–20. doi:10.1126/science.1111347. PMID 15890881. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=15890881.  
  101. ^ Karatygin IV, Snigirevskaya NS, Vikulin SV. (2009). "The most ancient terrestrial lichen Winfrenatia reticulata: A new find and new interpretation". Paleontological Journal 43 (1): 107–14. doi:10.1134/S0031030109010110. http://www.springerlink.com/content/g8l8708r5gr36646/fulltext.pdf.  
  102. ^ Taylor TN, Hass H, Kerp H, Krings M, Hanlin RT. (2005). "Perithecial Ascomycetes from the 400 million year old Rhynie chert: an example of ancestral polymorphism". Mycologia 97 (1): 269–85. doi:10.3852/mycologia.97.1.269. PMID 16389979.  
  103. ^ Dennis RL. (1970). "A Middle Pennsylvanian basidiomycete mycelium with clamp connections". Mycologia 62 (3): 578–84. doi:10.2307/3757529.  
  104. ^ Hibbett DS, Grimaldi D, Donoghue MJ. (1995). "Cretaceous mushrooms in amber". Nature 487: 487.  
  105. ^ Hibbett DS, Grimaldi D, Donoghue MJ. (1997). "Fossil mushrooms from Miocene and Cretaceous ambers and the evolution of homobasidiomycetes". American Journal of Botany 84 (7): 981–91. doi:10.2307/2446289.  
  106. ^ Eshet Y, Rampino MR, Visscher H. (1995). "Fungal event and palynological record of ecological crisis and recovery across the Permian-Triassic boundary". Geology 23 (1): 967–70. doi:10.1130/0091-7613(1995)023<0967:FEAPRO>2.3.CO;2.  
  107. ^ Foster CB, Stephenson MH, Marshall C, Logan GA, Greenwood PF. (2002). "A revision of Reduviasporonites Wilson 1962: description, illustration, comparison and biological affinities". Palynology 26 (1): 35–58. doi:10.2113/0260035. http://palynology.geoscienceworld.org/cgi/content/abstract/26/1/35.  
  108. ^ López-Gómez J, Taylor EL. (2005). "Permian-Triassic transition in Spain: a multidisciplinary approach". Palaeogeography, Palaeoclimatology, Palaeoecology 229 (1–2): 1–2. doi:10.1016/j.palaeo.2005.06.028. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6R-4GR8RWF-5&_user=1495569&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000053194&_version=1&_urlVersion=0&_userid=1495569&md5=537a1a5b0a8e04cca2221ecb12afb1e9.  
  109. ^ Looy CV, Twitchett RJ, Dilcher DL, Van Konijnenburg-van Cittert JHA, Visscher H. (2005). "Life in the end-Permian dead zone". Proceedings of the National Academy of Sciences USA 162 (4): 653–59. doi:10.1073/pnas.131218098. PMID 11427710. "See image 2".  
  110. ^ Ward PD, Botha J, Buick R, De Kock MO, Erwin DH, Garrison GH, Kirschvink JL, Smith R. (2005). "Abrupt and gradual extinction among late Permian land vertebrates in the Karoo Basin, South Africa". Science 307 (5710): 709–14. doi:10.1126/science.1107068. PMID 15661973.  
  111. ^ Shalchian-Tabrizi K, Minge MA, Espelund M, Orr R, Ruden T, Jakobsen KS, Cavalier-Smith T. (2008). "Multigene phylogeny of choanozoa and the origin of animals". PLoS ONE 3 (5): e2098. doi:10.1371/journal.pone.0002098. PMID 18461162. PMC 2346548. http://dx.plos.org/10.1371/journal.pone.0002098. Retrieved 2009-04-25.  
  112. ^ See Palaeos: Fungi for an introduction to fungal taxonomy, including recent controversies.
  113. ^ Celio GJ, Padamsee M, Dentinger BT, Bauer R, McLaughlin DJ. (2006). "Assembling the Fungal Tree of Life: constructing the structural and biochemical database". Mycologia 98 (6): 850–59. doi:10.3852/mycologia.98.6.850. PMID 17486962.  
  114. ^ Gill EE, Fast NM. (2006). "Assessing the microsporidia-fungi relationship: Combined phylogenetic analysis of eight genes". Gene 375: 103–9. doi:10.1016/j.gene.2006.02.023. PMID 16626896. http://linkinghub.elsevier.com/retrieve/pii/S0378-1119(06)00206-X.  
  115. ^ Liu YJ, Hodson MC, Hall BD. (2006). "Loss of the flagellum happened only once in the fungal lineage: phylogenetic structure of kingdom Fungi inferred from RNA polymerase II subunit genes". BMC Evolutionary Biology 6: 74. doi:10.1186/1471-2148-6-74. PMID 17010206. PMC 1599754. http://www.biomedcentral.com/1471-2148/6/74.  
  116. ^ a b Remy W, Taylor TN, Hass H, Kerp H. (1994). "4-hundred million year old vesicular-arbuscular mycorrhizae". Proceedings of the National Academy of Sciences USA 91 (25): 11841–43. doi:10.1073/pnas.91.25.11841. PMID 11607500.  
  117. ^ Schüssler A, Schwarzott D, Walker C. (2001). "A new fungal phylum, the Glomeromycota: phylogeny and evolution". Mycological Research 105 (12): 1413–21. doi:10.1017/S0953756201005196.  
  118. ^ Alexopoulos et al., p. 145.
  119. ^ For an example, see Samuels GJ. (2006). "Trichoderma: systematics, the sexual state, and ecology". Phytopathology 96 (2): 195–206. doi:10.1094/PHYTO-96-0195. PMID 18943925.  
  120. ^ Radford A, Parish JH. (1997). "The genome and genes of Neurospora crassa". Fungal Genetics and Biology: FG & B 21 (3): 258–66. doi:10.1006/fgbi.1997.0979. PMID 9290240. http://linkinghub.elsevier.com/retrieve/pii/S1087-1845(97)90979-8.  
  121. ^ Valverde ME, Paredes-López O, Pataky JK, Guevara-Lara F. (1995). "Huitlacoche (Ustilago maydis) as a food source—biology, composition, and production". Critical Reviews in Food Science and Nutrition 35 (3): 191–229. doi:10.1080/10408399509527699. PMID 7632354.  
  122. ^ Zisova LG. (2009). "Malassezia species and seborrheic dermatitis". Folia Medica 51 (1): 23–33. PMID 19437895.  
  123. ^ Perfect JR. (2006). "Cryptococcus neoformans: the yeast that likes it hot". FEMS Yeast Research 6 (4): 463–68. doi:10.1111/j.1567-1364.2006.00051.x. PMID 16696642.  
  124. ^ Blackwell M, Spatafora JW. (2004). "Fungi and their allies". in Bills GF, Mueller GM, Foster MS.. Biodiversity of Fungi: Inventory and Monitoring Methods. Amsterdam: Elsevier Academic Press. pp. 18–20. ISBN 0-12-509551-1.  
  125. ^ Shalchian-Tabrizi K, Minge MA, Espelund M, Orr R, Ruden T, Jakobsen KS, Cavalier-Smith T. (2008). "Multigene phylogeny of Choanozoa and the origin of animals". PLoS ONE 3 (5): e2098. doi:10.1371/journal.pone.0002098. PMID 18461162. PMC 2346548. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002098.  
  126. ^ Gadd GM. (2007). "Geomycology: biogeochemical transformations of rocks, minerals, metals and radionuclides by fungi, bioweathering and bioremediation". Mycological Research 111 (Pt 1): 3–49. doi:10.1016/j.mycres.2006.12.001. PMID 17307120. http://linkinghub.elsevier.com/retrieve/pii/S0953-7562(06)00336-4. Retrieved 2009-07-15.  
  127. ^ a b Lindahl BD, Ihrmark K, Boberg J, Trumbore SE, Högberg P, Stenlid J, Finlay RD (2007). "Spatial separation of litter decomposition and mycorrhizal nitrogen uptake in a boreal forest". New Phytologist 173 (3): 611–20. doi:10.1111/j.1469-8137.2006.01936.x. PMID 17244056.  
  128. ^ Barea JM, Pozo MJ, Azcón R, Azcón-Aguilar C. (2005). "Microbial co-operation in the rhizosphere". Journal of Experimental Botany 56 (417): 1761–78. doi:10.1093/jxb/eri197. PMID 15911555.  
  129. ^ Aanen DK. (2006). "As you reap, so shall you sow: coupling of harvesting and inoculating stabilizes the mutualism between termites and fungi". Biology Letters 2 (2): 209–12. doi:10.1098/rsbl.2005.0424. PMID 17148364.  
  130. ^ Nikoh N, Fukatsu T. (2000). "Interkingdom host jumping underground: phylogenetic analysis of entomoparasitic fungi of the genus Cordyceps". Molecular Biology and Evolution 17 (4): 2629–38. PMID 10742053.  
  131. ^ Perotto S, Bonfante P. (1997). "Bacterial associations with mycorrhizal fungi: close and distant friends in the rhizosphere". Trends in Microbiology 5 (12): 496–501. doi:10.1016/S0966-842X(97)01154-2. PMID 9447662.  
  132. ^ Arnold AE, Mejía LC, Kyllo D, Rojas EI, Maynard Z, Robbins N, Herre EA. (2003). "Fungal endophytes limit pathogen damage in a tropical tree". Proceedings of the National Academy of Sciences USA 100 (26): 15649–54. doi:10.1073/pnas.2533483100. PMID 14671327.  
  133. ^ a b Paszkowski U. (2006). "Mutualism and parasitism: the yin and yang of plant symbioses". Current Opinion in Plant Biology 9 (4): 364–70. doi:10.1016/j.pbi.2006.05.008. PMID 16713732.  
  134. ^ a b Hube B. (2004). "From commensal to pathogen: stage- and tissue-specific gene expression of Candida albicans". Current Opinion in Microbiology 7 (4): 336–41. doi:10.1016/j.mib.2004.06.003. PMID 15288621.  
  135. ^ Bonfante P. (2003). "Plants, mycorrhizal fungi and endobacteria: a dialog among cells and genomes". The Biological Bulletin 204 (2): 215–20. doi:10.2307/1543562. PMID 12700157. http://www.biolbull.org/cgi/content/full/204/2/215?view=long&pmid=12700157. Retrieved 2009-07-29.  
  136. ^ van der Heijden MG, Streitwolf-Engel R, Riedl R, Siegrist S, Neudecker A, Ineichen K, Boller T, Wiemken A, Sanders IR. (2006). "The mycorrhizal contribution to plant productivity, plant nutrition and soil structure in experimental grassland". New Phytologist 172 (4): 739–52. doi:10.1111/j.1469-8137.2006.01862.x. PMID 17096799.  
  137. ^ Selosse MA, Richard F, He X, Simard SW. (2006). "Mycorrhizal networks: des liaisons dangereuses?". Trends in Ecology and Evolution 21 (11): 621–28. doi:10.1016/j.tree.2006.07.003. PMID 16843567.  
  138. ^ Merckx V, Bidartondo MI, Hynson NA. (2009). "Myco-heterotrophy: when fungi host plants". Annals of Botany in press: 1255. doi:10.1093/aob/mcp235.  
  139. ^ Schulz B, Boyle C. (2005). "The endophytic continuum". Mycological Research 109 (Pt 6): 661–86. doi:10.1017/S095375620500273X. PMID 16080390.  
  140. ^ Clay K, Schardl C. (2002). "Evolutionary origins and ecological consequences of endophyte symbiosis with grasses". American Naturalist 160 Suppl 4: S99–S127. doi:10.1086/342161. PMID 18707456.  
  141. ^ Brodo IM, Sharnoff SD. (2001). Lichens of North America. Yale University Press. ISBN 0300082495.  
  142. ^ Raven PH, Evert RF, Eichhorn, SE. (2005). "14—Fungi". Biology of Plants (7 ed.). W. H. Freeman. p. 290. ISBN 978-0716710073.  
  143. ^ Deacon, p. 267.
  144. ^ Purvis W. (2000). Lichens. Washington, D.C.: Smithsonian Institution Press in association with the Natural History Museum, London. pp. 49–75. ISBN 1-56098-879-7.  
  145. ^ Kirk et al., p. 378.
  146. ^ Deacon, pp. 267–76.
  147. ^ Douglas AE. (1989). "Mycetocyte symbiosis in insects". Biological Reviews of the Cambridge Philosophical Society 64 (4): 409–34. doi:10.1111/j.1469-185X.1989.tb00682.x. PMID 2696562.  
  148. ^ Deacon, p. 277.
  149. ^ Aanen DK. (2006). "As you reap, so shall you sow: coupling of harvesting and inoculating stabilizes the mutualism between termites and fungi". Biology Letters 2 (2): 209–12. doi:10.1098/rsbl.2005.0424. PMID 17148364. PMC 1618886. http://rsbl.royalsocietypublishing.org/cgi/pmidlookup?view=long&pmid=17148364. Retrieved 2009-04-25.  
  150. ^ Nguyen NH, Suh SO, Blackwell M. (2007). "Five novel Candida species in insect-associated yeast clades isolated from Neuroptera and other insects". Mycologia 99 (6): 842–58. doi:10.3852/mycologia.99.6.842. PMID 18333508.  
  151. ^ Talbot NJ. (2003). "On the trail of a cereal killer: Exploring the biology of Magnaporthe grisea". Annual Reviews in Microbiology 57: 177–202. doi:10.1146/annurev.micro.57.030502.090957. PMID 14527276.  
  152. ^ Paoletti M, Buck KW, Brasier CM. (2006). "Selective acquisition of novel mating type and vegetative incompatibility genes via interspecies gene transfer in the globally invading eukaryote Ophiostoma novo-ulmi". Molecular Ecology 15 (1): 249–62. doi:10.1111/j.1365-294X.2005.02728.x. PMID 16367844.  
  153. ^ Gryzenhout M, Wingfield BD, Wingfield MJ. (2006). "New taxonomic concepts for the important forest pathogen Cryphonectria parasitica and related fungi". FEMS Microbiology Letters 258 (2): 161–72. doi:10.1111/j.1574-6968.2006.00170.x. PMID 16640568.  
  154. ^ Yang Y, Yang E, An Z, Liu X. (2007). "Evolution of nematode-trapping cells of predatory fungi of the Orbiliaceae based on evidence from rRNA-encoding DNA and multiprotein sequences". Proceedings of the National Academy of Sciences USA 104 (20): 8379–84. doi:10.1073/pnas.0702770104. PMID 17494736. PMC 1895958. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=17494736. Retrieved 2009-04-25.  
  155. ^ Nielsen K, Heitman J. (2007). "Sex and virulence of human pathogenic fungi". Advances in Genetics 57: 143–73. doi:10.1016/S0065-2660(06)57004-X. PMID 17352904.  
  156. ^ Brakhage AA. (2005). "Systemic fungal infections caused by Aspergillus species: epidemiology, infection process and virulence determinants". Current Drug Targets 6 (8): 875–86. doi:10.2174/138945005774912717. PMID 16375671.  
  157. ^ Kauffman CA. (2007). "Histoplasmosis: a clinical and laboratory update". Clinical Microbiology Reviews 20 (1): 115–32. doi:10.1128/CMR.00027-06. PMID 17223625.  
  158. ^ Cushion MT, Smulian AG, Slaven BE, Sesterhenn T, Arnold J, Staben C, Porollo A, Adamczak R, Meller J. (2007). "Transcriptome of Pneumocystis carinii during fulminate infection: carbohydrate metabolism and the concept of a compatible parasite". PLoS ONE 2 (5): e423. doi:10.1371/journal.pone.0000423. PMID 17487271.  
  159. ^ Cook GC, Zumla AI. (2008). Manson's Tropical Diseases: Expert Consult. Saunders Ltd. p. 347. ISBN 1-4160-4470-1.  
  160. ^ Simon-Nobbe B, Denk U, Pöll V, Rid R, Breitenbach M. (2008). "The spectrum of fungal allergy". International Archives of Allergy and Immunology 145 (1): 58–86. doi:10.1159/000107578. PMID 17709917.  
  161. ^ Fincham JRS. (1989). "Transformation in fungi". Microbiological Reviews 53 (1): 148–70. PMID 2651864. PMC 372721. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=2651864.  
  162. ^ Hawkins KM, Smolke CD. (2008). "Production of benzylisoquinoline alkaloids in Saccharomyces cerevisiae". Nature Chemical Biology 4 (9): 564–73. doi:10.1038/nchembio.105. PMID 18690217.  
  163. ^ Huang B, Guo J, Yi B, Yu X, Sun L, Chen W. (2008). "Heterologous production of secondary metabolites as pharmaceuticals in Saccharomyces cerevisiae". Biotechnology Letters 30 (7): 1121–37. doi:10.1007/s10529-008-9663-z. PMID 18512022.  
  164. ^ Brakhage AA, Spröte P, Al-Abdallah Q, Gehrke A, Plattner H, Tüncher A. (2004). "Regulation of penicillin biosynthesis in filamentous fungi". Advances in Biochemical Engineering/biotechnology 88: 45–90. PMID 15719552.  
  165. ^ Loo DS. (2006). "Systemic antifungal agents: an update of established and new therapies". Advances in Dermatology 22: 101–24. doi:10.1016/j.yadr.2006.07.001. PMID 17249298.  
  166. ^ Pan A, Lorenzotti S, Zoncada A. (2008). "Registered and investigational drugs for the treatment of methicillin-resistant Staphylococcus aureus infection". Recent Patents on Anti-infective Drug Discovery 3 (1): 10–33. doi:10.2174/157489108783413173. PMID 18221183.  
  167. ^ Fajardo A, Martínez JL. (2008). "Antibiotics as signals that trigger specific bacterial responses". Current Opinion in Microbiology 11 (2): 161–67. doi:10.1016/j.mib.2008.02.006. PMID 18373943.  
  168. ^ Kulp K. (2000). Handbook of Cereal Science and Technology. CRC Press. ISBN 0824782941.  
  169. ^ Piskur J, Rozpedowska E, Polakova S, Merico A, Compagno C. (2006). "How did Saccharomyces evolve to become a good brewer?". Trends in Genetics 22 (4): 183–86. doi:10.1016/j.tig.2006.02.002. PMID 16499989.  
  170. ^ Abe K, Gomi K, Hasegawa F, Machida M. (2006). "Impact of Aspergillus oryzae genomics on industrial production of metabolites". Mycopathologia 162 (3): 143–53. doi:10.1007/s11046-006-0049-2. PMID 16944282.  
  171. ^ Hachmeister KA, Fung DY (1993). "Tempeh: a mold-modified indigenous fermented food made from soybeans and/or cereal grains". Critical Reviews in Microbiology 19 (3): 137–88. doi:10.3109/10408419309113527. PMID 8267862.  
  172. ^ Jørgensen TR. (2007). "Identification and toxigenic potential of the industrially important fungi, Aspergillus oryzae and Aspergillus sojae". Journal of Food Protection 70 (12): 2916–34. PMID 18095455.  
  173. ^ O'Donnell K, Cigelnik E, Casper HH. (1998). "Molecular phylogenetic, morphological, and mycotoxin data support reidentification of the Quorn mycoprotein fungus as Fusarium venenatum". Fungal Genetics and Biology 23 (1): 57–67. doi:10.1006/fgbi.1997.1018. PMID 9501477. http://linkinghub.elsevier.com/retrieve/pii/S1087-1845(97)91018-5.  
  174. ^ a b Hetland G, Johnson E, Lyberg T, Bernardshaw S, Tryggestad AM, Grinde B. (2008). "Effects of the medicinal mushroom Agaricus blazei Murill on immunity, infection and cancer". Scandinavian Journal of Immunology 68 (4): 363–70. doi:10.1111/j.1365-3083.2008.02156.x. PMID 18782264.  
  175. ^ Firenzuoli F, Gori L, Lombardo G. (2008). "The medicinal mushroom Agaricus blazei Murrill: review of literature and pharmaco-toxicological problems". Evidence-based Complementary and Alternative Medicine: eCAM 5 (1): 3–15. doi:10.1093/ecam/nem007. PMID 18317543. PMC 2249742. http://ecam.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=18317543.  
  176. ^ Paterson RR. (2006). "Ganoderma – a therapeutic fungal biofactory". Phytochemistry 67 (18): 1985–2001. doi:10.1002/chin.200650268. PMID 16905165.  
  177. ^ Paterson RR. (2008). "Cordyceps: a traditional Chinese medicine and another fungal therapeutic biofactory?". Phytochemistry 69 (7): 1469–95. doi:10.1016/j.phytochem.2008.01.027. PMID 18343466.  
  178. ^ el-Mekkawy S, Meselhy MR, Nakamura N, Tezuka Y, Hattori M, Kakiuchi N, Shimotohno K, Kawahata T, Otake T. (1998). "Anti-HIV-1 and anti-HIV-1-protease substances from Ganoderma lucidum". Phytochemistry 49 (6): 1651–57. doi:10.1016/S0031-9422(98)00254-4. PMID 9862140.  
  179. ^ El Dine RS, El Halawany AM, Ma CM, Hattori M. (2008). "Anti-HIV-1 protease activity of lanostane triterpenes from the vietnamese mushroom Ganoderma colossum". Journal of Natural Products 71 (6): 1022–26. doi:10.1021/np8001139. PMID 18547117.  
  180. ^ Yuen JW, Gohel MD. (2005). "Anticancer effects of Ganoderma lucidum: a review of scientific evidence". Nutrition and Cancer 53 (1): 11–17. doi:10.1207/s15327914nc5301_2. PMID 16351502.  
  181. ^ Sullivan R, Smith JE, Rowan NJ. (2006). "Medicinal mushrooms and cancer therapy: translating a traditional practice into Western medicine". Perspectives in Biology and Medicine 49 (2): 159–70. doi:10.1353/pbm.2006.0034. PMID 16702701.  
  182. ^ Halpern GM, Miller A. (2002). Medicinal Mushrooms: Ancient Remedies for Modern Ailments. New York: M. Evans and Co. p. 116. ISBN 0-87131-981-0.  
  183. ^ Fisher M, Yang LX. (2002). "Anticancer effects and mechanisms of polysaccharide-K (PSK): implications of cancer immunotherapy". Anticancer Research 22 (3): 1737–54. PMID 12168863.  
  184. ^ Stamets P. (2000). Growing Gourmet and Medicinal Mushrooms = [Shokuyō oyobi yakuyō kinoko no saibai]. Berkeley, Calif: Ten Speed Press. pp. 233–48. ISBN 1-58008-175-4.  
  185. ^ Hall, pp. 13–26.
  186. ^ Kinsella JE, Hwang DH. (1976). "Enzymes of Penicillium roqueforti involved in the biosynthesis of cheese flavor". CRC Critical Reviews in Food Science and Nutrition 8 (2): 191–228. doi:10.1080/10408397609527222. PMID 21770.  
  187. ^ Erdogan A, Gurses M, Sert S. (2004). "Isolation of moulds capable of producing mycotoxins from blue mouldy Tulum cheeses produced in Turkey". International Journal of Food Microbiology 85 (1-2): 83–85. doi:10.1016/S0168-1605(02)00485-3. PMID 12810273.  
  188. ^ Orr DB, Orr RT. (1979). Mushrooms of Western North America. Berkeley: University of California Press. p. 17. ISBN 0-520-03656-5.  
  189. ^ Vetter J. (1998). "Toxins of Amanita phalloides". Toxicon 36 (1): 13–24. doi:10.1016/S0041-0101(97)00074-3. PMID 9604278.  
  190. ^ Leathem AM, Dorran TJ. (2007). "Poisoning due to raw Gyromitra esculenta (false morels) west of the Rockies". Canadian Journal of Emergency Medicine 9 (2): 127–30. PMID 17391587.  
  191. ^ Karlson-Stiber C, Persson H. (2003). "Cytotoxic fungi—an overview". Toxicon 42 (4): 339–49. doi:10.1016/S0041-0101(03)00238-1. PMID 14505933.  
  192. ^ Michelot D, Melendez-Howell LM. (2003). "Amanita muscaria: chemistry, biology, toxicology, and ethnomycology". Mycological Research 107 (Pt 2): 131–46. doi:10.1017/S0953756203007305. PMID 12747324.  
  193. ^ Hall, p. 7.
  194. ^ Ammirati JF, McKenny M, Stuntz DE. (1987). The New Savory Wild Mushroom. Seattle: University of Washington Press. pp. xii – xiii. ISBN 0-295-96480-4.  
  195. ^ López-Gómez J, Molina-Meyer M. (2006). "The competitive exclusion principle versus biodiversity through competitive segregation and further adaptation to spatial heterogeneities". Theoretical Population Biology 69 (1): 94–109. doi:10.1016/j.tpb.2005.08.004. PMID 16223517.  
  196. ^ Becker H. (1998). "Setting the Stage To Screen Biocontrol Fungi". United States Department of Agriculture, Agricultural Research Service. http://www.ars.usda.gov/is/AR/archive/jul98/fung0798.htm. Retrieved 2009-02-23.  
  197. ^ Keiller TS. "Whey-based fungal microfactory technology for enhanced biological pest management using fungi" (PDF). UVM Innovations. http://www.uvminnovations.com/graphics/microfactory.pdf. Retrieved 2009-02-23.  
  198. ^ Deshpande MV. (1999). "Mycopesticide production by fermentation: potential and challenges". Critical Reviews in Microbiology 25 (3): 229–43. doi:10.1080/10408419991299220. PMID 10524330.  
  199. ^ Thomas MB, Read AF. (2007). "Can fungal biopesticides control malaria?". Nature Reviews in Microbiology 5 (5): 377–83. doi:10.1038/nrmicro1638. PMID 17426726.  
  200. ^ Bush LP, Wilkinson HH, Schardl CL. (1997). "Bioprotective alkaloids of grass-fungal endophyte symbioses". Plant Physiology 114 (1): 1–7. PMID 12223685.  
  201. ^ Bouton JH, Latch GCM, Hill NS, Hoveland CS, McCannc MA, Watson RH, Parish JA, Hawkins LL, Thompson FN. (2002). "Use of nonergot alkaloid-producing endophytes for alleviating tall fescue toxicosis in sheep". Agronomy Journal 94: 567–74. http://agron.scijournals.org/cgi/content/full/94/3/567.  
  202. ^ Christian V, Shrivastava R, Shukla D, Modi HA, Vyas BR. (2005). "Degradation of xenobiotic compounds by lignin-degrading white-rot fungi: enzymology and mechanisms involved". Indian Journal of Experimental Biology 43 (4): 301–12. PMID 15875713.  
  203. ^ BBC (2008). Fungi to fight 'toxic war zones'|accessed 2009-07-29
  204. ^ Fomina M, Charnock JM, Hillier S, Alvarez R, Livens F, Gadd GM. (2008). "Role of fungi in the biogeochemical fate of depleted uranium". Current Biology 18 (9): R375–77. doi:10.1016/j.cub.2008.03.011. PMID 18460315.  
  205. ^ Fomina M, Charnock JM, Hillier S, Alvarez R, Gadd GM. (2007). "Fungal transformations of uranium oxides". Environmental Microbiology 9 (7): 1696–710. doi:10.1111/j.1462-2920.2007.01288.x. PMID 17564604.  
  206. ^ Beadle GW, Tatum EL. (1941). "Genetic control of biochemical reactions in Neurospora". Proceedings of the National Academy of Sciences of the USA 27 (11): 499–506. doi:10.1073/pnas.27.11.499. PMID 16588492. PMC 1078370. http://www.pnas.org/content/27/11/499.short.  
  207. ^ Datta A, Ganesan K, Natarajan K. (1989). "Current trends in Candida albicans research". Advances in Microbial Physiology 30: 53–88. doi:10.1016/S0065-2911(08)60110-1. PMID 2700541.  
  208. ^ Dean RA, Talbot NJ, Ebbole DJ, et al. (2005). "The genome sequence of the rice blast fungus Magnaporthe grisea". Nature 434 (7036): 980–86. doi:10.1038/nature03449. PMID 15846337.  
  209. ^ Daly R, Hearn MT. (2005). "Expression of heterologous proteins in Pichia pastoris: a useful experimental tool in protein engineering and production". Journal of Molecular Recognition: JMR 18 (2): 119–38. doi:10.1002/jmr.687. PMID 15565717.  
  210. ^ Schlegel HG. (1993). General Microbiology. Cambridge, UK: Cambridge University Press. p. 360. ISBN 0-521-43980-9.  
  211. ^ "Trichoderma spp., including T. harzianum, T. viride, T. koningii, T. hamatum and other spp. Deuteromycetes, Moniliales (asexual classification system)". Biological Control: A Guide to Natural Enemies in North America. http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/trichoderma.html. Retrieved 2007-07-10.  
  212. ^ Joseph B, Ramteke PW, Thomas G. (2008). "Cold active microbial lipases: some hot issues and recent developments". Biotechnology Advances 26 (5): 457–70. doi:10.1016/j.biotechadv.2008.05.003. PMID 18571355.  
  213. ^ Olempska-Beer ZS, Merker RI, Ditto MD, DiNovi MJ. (2006). "Food-processing enzymes from recombinant microorganisms—a review". Regulatory Toxicology and Pharmacology 45 (2): 144–58. doi:10.1016/j.yrtph.2006.05.001. PMID 16769167.  
  214. ^ Kumar R, Singh S, Singh OV. (2008). "Bioconversion of lignocellulosic biomass: biochemical and molecular perspectives". Journal of Industrial Microbiology and Biotechnology 35 (5): 377–91. doi:10.1007/s10295-008-0327-8. PMID 18338189.  
  215. ^ Polizeli ML, Rizzatti AC, Monti R, Terenzi HF, Jorge JA, Amorim DS. (2005). "Xylanases from fungi: properties and industrial applications". Applied Microbiology and Biotechnology 67 (5): 577–91. doi:10.1007/s00253-005-1904-7. PMID 15944805.  
  216. ^ Schardl CL, Panaccione DG, Tudzynski P. (2006). "Ergot alkaloids—biology and molecular biology". The Alkaloids. Chemistry and Biology 63: 45–86. doi:10.1016/S1099-4831(06)63002-2. PMID 17133714.  
  217. ^ van Egmond HP, Schothorst RC, Jonker MA. (2007). "Regulations relating to mycotoxins in food: perspectives in a global and European context". Analytical and Bioanalytical Chemistry 389 (1): 147–57. doi:10.1007/s00216-007-1317-9. PMID 17508207.  
  218. ^ Keller NP, Turner G, Bennett JW. (2005). "Fungal secondary metabolism – from biochemistry to genomics". Nature Reviews in Microbiology 3 (12): 937–47. doi:10.1038/nrmicro1286. PMID 16322742.  
  219. ^ Demain AL, Fang A. (2000). "The natural functions of secondary metabolites". Advances in Biochemical Engineering/Biotechnology 69: 1–39. doi:10.1007/3-540-44964-7_1. PMID 11036689.  
  220. ^ Rohlfs M, Albert M, Keller NP, Kempken F. (2007). "Secondary chemicals protect mould from fungivory". Biology Letters 3 (5): 523–5. doi:10.1098/rsbl.2007.0338. PMID 17686752.  
  221. ^ According to one 2001 estimate, some 10,000 fungal diseases are known. Struck C. (2006). "Infection strategies of plant parasitic fungi". in Cooke BM, Jones DG, Kaye B. The Epidemiology of Plant Diseases. Berlin: Springer. p. 117. ISBN 1-4020-4580-8.  
  222. ^ Peintner U, Pöder R, Pümpel T. (1998). "The Iceman's fungi". Mycological Research 102 (10): 1153–62. doi:10.1017/S0953756298006546.  
  223. ^ Ainsworth, p. 1.
  224. ^ Alexopoulos et al., pp. 1–2.
  225. ^ Ainsworth, p. 18.
  226. ^ Hawksworth DL. (2006). "Pandora's Mycological Box: Molecular sequences vs. morphology in understanding fungal relationships and biodiversity". Revista Iberoamericana de Micologia 23 (3): 127–33. doi:10.1016/S1130-1406(06)70031-6. PMID 17196017.  

References

  • Ainsworth GC. (1976). Introduction to the History of Mycology. Cambridge, UK: Cambridge University Press. ISBN 0-521-11295-8.  
  • Alexopoulos CJ, Mims CW, Blackwell M. (1996). Introductory Mycology. John Wiley and Sons. ISBN 0471522295.  
  • Deacon J. (2005). Fungal Biology. Cambridge, MA: Blackwell Publishers. ISBN 1-4051-3066-0.  
  • Hall IR. (2003). Edible and Poisonous Mushrooms of the World. Portland, Oregon: Timber Press. ISBN 0-88192-586-1.  
  • Hanson JR. (2008). The Chemistry of Fungi. Royal Society Of Chemistry. ISBN 0854041362.  
  • Jennings DH, Lysek G. (1996). Fungal Biology: Understanding the Fungal Lifestyle. Guildford, UK: Bios Scientific Publishers Ltd. ISBN 978-1859961506.  
  • Kirk PM, Cannon PF, Minter DW, Stalpers JA. (2008). Dictionary of the Fungi. 10th ed. Wallingford: CABI. ISBN 0-85199-826-7.  
  • Taylor EL, Taylor TN. (1993). The Biology and Evolution of Fossil Plants. Englewood Cliffs, N.J: Prentice Hall. ISBN 0-13-651589-4.  

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

FUNGI (pl. of Lat. fungus, a mushroom), the botanical name covering in the broad sense all the lower cellular Cryptogams devoid of chlorophyll, which arise from spores, and the thallus of which is either unicellular or composed of branched or unbranched tubes or cell-filaments (hyphae) with apical growth, or of more or less complex wefted sheets or tissue-like masses of such (mycelium). The latter may in certain cases attain large dimensions, and even undergo cell-divisions in their interior, resulting in the development of true tissues. The spores, which may be unior multi-cellular, are either abstricted free from the ends of hyphae (acrogenous), or formed from segments in their course (chlamydospores) or from protoplasm in their interior (endogenous). The want of chlorophyll restricts their mode of life - which is rarely aquatic - since they are therefore unable to decompose the carbon dioxide of the atmosphere, and renders them dependent on other plants or (rarely) animals for their carbonaceous food-materials. These they obtain usually in the form of carbohydrates from the dead remains of other organisms, or in this or other forms from the living cells of their hosts; in the former case they are termed saprophytes, in the latter parasites. While some moulds (Penicillium, Aspergillus) can utilize almost any organic food-materials, other fungi are more restricted in their choice - e.g. insect-parasites, hornand feather-destroying fungi and parasites generally. It was formerly the custom to include with the Fungi the Schizomycetes or Bacteria, and the Myxomycetes or Mycetozoa; but the peculiar mode of growth and division, the cilia, spores and other peculiarities of the former, and the emission of naked amoeboid masses of protoplasm, which creep and fuse to streaming plasmodia, with special modes of nutrition and spore-formation of the latter, have led to their separation as groups of organisms independent of the true Fungi. On the other hand, lichens, previously regarded as autonomous plants, are now known to be dual organisms - fungi symbiotic with algae.

The number of species in 1889 was estimated by Saccardo at about 32,000, but of these 8500 were so-called Fungi imperfecti - i.e. forms of which we only know certain stages, such as conidia, pycnidia, &c., and which there are reasons for regarding as merely the corresponding stages of higher forms. Saccardo also included about 400 species of Myxomycetes and 650 of Schizomycetes. Allowing for these and for the cases, undoubtedly not few, where one and the same fungus has been described under different names, we obtain Schroeter's estimate (in 1892) of 20,000 species.

In illustration of the very different estimates that have been made, however, may be mentioned that of De Bary in 1872 of 150,000 species, and that of Cooke in 1895 of 40,000, and Massee in 1899 of over 50,000 species, the fact being that no sufficient data are as yet to hand for any accurate census. As regards their geographical distribution, fungi, like flowering plants, have no doubt their centres of origin and of dispersal; but we must not forget that every exchange of wood, wheat, fruits, plants, animals, or other commodities involves transmission of fungi from one country to another; while the migrations of birds and other animals, currents of air and water, and so forth, are particularly efficacious in transmitting these minute organisms. Against this, of course, it may be argued that parasitic forms can only go where their hosts grow, as is proved to be the case by records concerning the introduction of Puccinia malvacearum, Peronospora viticola, Hemileia vastatrix, &c. Some fungi - e.g. moulds and yeasts - appear to be distributed all over the earth. That the north temperate regions appear richest in fungi may be due only to the fact that North America and Europe have been much more thoroughly investigated than other countries; it is certain that the tropics are the home of very numerous species. Again, the accuracy of the statement that the fleshy Agaricini, Polyporei, Pezizae, &c., are relatively rarer in the tropics may depend on the fact that they are more difficult to collect and remit for identification than the abundantly recorded woody and coriaceous forms of these regions. When we remember that many parts of the world are practically unexplored as regards fungi, and that new species are constantly being discovered in the United States, Australia and northern Europe - the best explored of all - it is clear that no very accurate census of fungi can as yet be made, and no generalizations of value as to their geographical distribution are possible.

The existence of fossil fungi is undoubted, though very few of the identifications can be relied on as regards species or genera. They extend back beyond the Carboniferous, where they occur as hyphae, &c., preserved in the fossil woods, but the best specimens are probably those in amber and in siliceous petrifactions of more recent origin.

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Table of contents

Organs

Individual hyphae or their branches often exhibit specializations of form. In many Basidiomycetes minute branches arise below the septa; their tips curve over the outside of the latter, and fuse with the cell above just beyond it, forming a clamp-connexion. Many parasitic hyphae put out minute lateral branches, which pierce the cell-wall of the host and form a peg-like (Trichosphaeria), sessile (Cystopus), or stalked (Hemileia), knot-like, or_a B FIG. I.-I, Peronospora parasitica (De Bary). Mycelium with haustoria (h); 2, Erysiphe; A and B, mycelium (m), with haustoria (h). (After De Bary.) more or less branched (Peronospora) or coiled (Protomyces)haustorium. In Rhizopus certain hyphae creep horizontally on the surface of the substratum, and then anchor their tips to it by means of a tuft of short branches (appressorium), the walls of which soften and gum themselves to it, then another branch shoots out from the tuft and repeats the process, like a strawberry-runner. Appressoria are also formed by some parasitic fungi, as a minute flattening of the tip of a very short branch (Erysiphe), or the swollen end of any hypha which comes in contact with the surface of the host (Piptocephalis, Syncephalis), haustoria piercing in each case the cell-wall below. In Botrytis the appressoria assume the form of dense tassels of short branches. In Arthrobotrys side-branches of the mycelium sling themselves around the host (Tylenchus) much as tendrils round a support.

Many fungi (Phallus, Agaricus, Fumago, &c.) when strongly growing put out ribbon-like or cylindrical cords, or sheet-like mycelial plates of numerous parallel hyphae, all growing together equally, and fusing by anastomoses, and in this way extend long distances in the soil, or over the surfaces of leaves, branches, &c. These mycelial strands may be white and tender, or the outer hyphae may be hard and black, and very often the resemblance of the subterranean forms to a root is so marked that they are termed rhizomorphs. The outermost hyphae may even put forth thinner hyphae, radiating into the soil like root-hairs, and the convergent tips may be closely appressed and so divided by septa as to resemble the root-apex of a higher plant (Armillaria mellea). Sclerotia. - Fungi, like other plants, are often found to store up large quantities of reserve materials (oil, glycogen, carbohydrates, &c.) in special parts of their vegetative tissues, where they lie accumulated between a period of active assimilation and one of renewed activity, forming reserves to be consumed particularly during the formation of large fructifications. These reserve stores may be packed away in single hyphae or in swollen cells, but the hyphae containing them are often gathered into thick cords or mycelial strands (Phallus, mushroom, &c.), or flattened and anastomosing ribbons and plates, often containing several kinds of hyphae (Merulius lacrymans). In other cases the strands undergo differentiation into an outer layer with blackened, hardened cell-walls and a core of ordinary hyphae, and are then termed rhizomorphs (Armillaria mellea), capable not only of extending the fungus in the soil, like roots, but also of lying dormant, protected by the outer casing. Such aggregations of hyphae frequently become knotted up into dense masses of interwoven and closely packed hyphae, varying in size from that of a pin's head or a pea (Peziza, Coprinus) to that of a man's fist or head, and weighing io to 25 lb or more (Polyporus Mylittae, P. tumulosus, Lentinus Woermanni, P. Sapurema, &c.). The interwoven hyphae fuse and branch copiously, filling up all interstices. They also undergo cutting up by numerous septa into short cells, and these often divide again in all planes, so that a pseudoparenchyma results, the walls of which may be thickened and swollen internally, or hardened and black on the exterior. In many cases the swollen cell-walls serve as reserves, and sometimes the substance is so thickly deposited in strata as to obliterate the lumen, and the hyphae become nodular (Polyporus sacer, P. rhinoceros, Lentinus Woermanni). The various sclerotia, if kept moist, give rise to the fructifications of the fungi concerned, much as a potato tuber does to a potato plant, and in the same way the reserve materials are consumed. They are principally Polyporei, Agaricini, Pezizae; none are known among the Phycomycetes, Uredineae or Ustilagineae. The functions of mycelial strands, rhizomorphs and sclerotia are not only to collect and store materials, but also to extend the fungus, and in many cases similar strands act as organs of attack. The same functions of storage in advance of fructification are also exercised by the stromata so common in Ascomycetes.

Tissue Dif f erentiations

The simpler mycelia consist of hyphae all alike and thin-walled, or merely differing in the diameter of the branches of various orders, or in their relations to the environment, some plunging into the substratum like roots, others remaining on its surface, and others (aerial hyphae) rising into the air. Such hyphae may be multicellular, or they may consist of simple tubes with numerous nuclei and no septa (Phycomycetes), and are then non-cellular. In the more complex tissue-bodies of higher fungi, however, we find considerable differences in the various layers or strands of hyphae.

An epidermis-like or cortical protective outer layer is very common, and is usually characterized by the close septation of the densely interwoven hyphae and the thickening and dark colour of their outer walls (sclerotia, Xylaria, &c.). Fibre-like hyphae with the lumen almost obliterated by the thick walls occur in mycelial cords (Merulius). Latex-tubes abound in the tissues of Lactarius, Stereum, Mycena, Fistulina, filled with white or coloured milky fluids, and Istvanffvi has shown that similar tubes with fluid or oily contents are widely spread in other Hymenomycetes. Sometimes fatty oil or watery sap is found in swollen hyphal ends, or such tubes contain coloured sap. Cystidia and paraphyses may be also classed here. In Merulius lacrymans Hartig has observed thin-walled hyphae with large lumina, the septa of which are perforated like those of sieve-tubes.

As regards its composition, the cell-wall of fungi exhibits variations of the same kind as those met with in higher plants. While the fundamental constituent is a cellulose in many Mucorini and other Phycomycetes, in others bodies like pectose, callose, &c., commonly occur, and Wisselingh's researches show that chitin, a gluco-proteid common in animals, forms the main constituent in many cases, and is probably deposited directly as such, though, like the other substances, it may be mixed with cellulose. As in other cell-walls, so here the older membranes may be altered by deposits of various substances, such as resin, calcium oxalate, colouring matters; or more profoundly altered throughout, or in definite layers, by lignification, suberization (Trametes, Daedalea), or swelling to a gelatinous mucilage (Tremella, Gymnosporangium), while cutinization of the outer layers is common. One of the most striking alterations of cell-walls is that termed carbonization, in which the substance gradually turns black, hard and brittle, as if charred - e.g. Xylaria, Ustulina, some sclerotia. At the other extreme the cell-walls of many lichen-fungi are soft and colourless, but turn blue in iodine, as does starch. The young cell-wall is always tenuous and flexible, and may remain so throughout, but in many cases thickenings and structural differentiations, as well as the changes referred to above, alter the primary wall considerably. Such thickening may be localized, and pits (e.g. Uredospores, septa of Basidiomycetes), spirals, reticulations, rings, &c. (capillitium fibres of Podaxon, Calostoma, Battarrea), occur as in the vessels of higher plants, while sculptured networks, pittings and so forth are as common on fungus-spores as they are on pollen grains.

Cell-Contents

The cells of fungi, in addition to protoplasm, nuclei and sap-vacuoles, like other vegetable cells, contain formed and amorphous bodies of various kinds. Among those directly visible to the microscope are oil drops, often coloured (Uredineae) crystals of calcium oxalate (Phallus, Russula), proteid crystals (Mucor, Pilobolus, &c.) and resin (Polyporei). The oidia of Erysipheae contain fibrosin bodies and the hyphae of Saprolegnieae cellulin bodies, but starch apparently never occurs. Invisible to the microscope, but rendered visible by reagents, are glycogen, Mucor, Ascomycetes, yeast, &c. In addition to these cell-contents we have good indirect evidence of the existence of large series of other bodies, such as proteids, carbohydrates, organic acids, alkaloids, enzymes, &c. These must not be confounded with the numerous substances obtained by chemical analysis of masses of the fungus, as there is often no proof of the manner of occurrence of such bodies, though we may conclude with a good show of probability that some of them also exist preformed in the living cell. Such are sugars (glucose, mannite, &c.), acids (acetic, citric and a whole series of lichen-acids), ethereal oils and resinous bodies, often combined with the intense colours of fungi and lichens, and a number of powerful alkaloid poisons, such as muscarin (Amanita), ergotin (Claviceps), &c.

Among the enzymes already extracted from fungi are invertases (yeasts, moulds, &c.), which split cane-sugar and other complex sugars with hydrolysis into simpler sugars such as dextrose and levulose; diastases, which convert starches into sugars (Aspergillus, &c.); cytases, which dissolve cellulose similarly (Botrytis, &c.); peptases, using the term as a general one for all enzymes which convert proteids into peptones and other bodies (Penicillium, &c.); lipases, which break up fatty oils (Empusa, Phycomyces, &c.); oxydases, which bring about the oxidations and changes of colour observed in Boletus, and zymase, extracted by Buchner from yeast, which brings about the conversion of sugar into alcohol and carbondioxide. That such enzymes are formed in the protoplasm is evident from the behaviour of hyphae, which have been observed to pierce cell-membranes, the chitinous coats of insects, artificial collodion films and layers of wax, &c. That a fungus can secrete more than one enzyme, according to the materials its hyphae have to attack, has been shown by the extraction of diastase, inulase, trehalase, invertase, maltase, raffinase, malizitase, emulsin, trypsin and lipase from Aspergillus by Bourquelot, and similar events occur in other fungi. The same fact is indicated by the wide range of organic substances which can be utilized by Penicillium and other moulds, and by the behaviour of parasitic fungi which destroy various cell-contents and tissues. Many of the coloured pigments of fungi are fixed in the cell-walls or excreted to the outside (Peziza aeruginosa). Matruchot has used them for staining the living protoplasm of other fungi by growing the two together. Striking instances of coloured mycelia are afforded by Corticiunt sanguineum, blood - red; Elaphomyces Leveillei, yellow - green; Chlorosplenium aeruginosum, verdigris green; and the Dematei, brown or black.

Nuclei

Although many fungi have been regarded as devoid of nuclei, and all have not as yet been proved to contain them, the numerous investigations of recent years have revealed them in the cells of all forms thoroughly examined, and we are justified in concluding that the nucleus is as essential to the cell of a fungus as to that of other organisms. The hyphae of many contain numerous, even hundreds of nuclei (Phycomycetes); those of others have several (Aspergillus) in each segment, or only two (Exoascus) or one (Erysiphe) in each cell. Even the isolated cells of the yeast plant have each one nucleus. As a rule the nuclei of the mycelium are very minute (1.5-2 µ in Phycomyces), but those of many asci and spores are large and easily rendered visible. As with other plants, so in fungi the essential process of fertilization consists in the fusion of two nuclei, but owing to the absence of well-marked sexual organs from many fungi, a peculiar interest attaches to certain nuclear fusions in the vegetative cells or in young spores of many forms. Thus in Ustilagineae the chlamydospores, and in Uredineae the teleutospores, each contain two nuclei when young, which fuse as the spores mature. In young asci a similar fusion of two nuclei occurs, and also in basidia, in each case the nucleus of the ascus or of the basidium resulting from the fusion subsequently giving rise by division to the nuclei of the ascospores and basidiospores respectively. The significance of these fusions will be discussed under the various groups. Nuclear division is usually accompanied by all the essential features of karyokinesis.

Spores

No agreement has ever been arrived at regarding the consistent use of the term spore. This is apparently owing to the facts that too much has been attempted in the definition, and that differences arise according as we aim at a morphological or a physiological definition. Physiologically, any cell or group of cells separated off from a hypha or unicellular fungus, and capable of itself growing out - germinating - to reproduce the fungus, is a spore; but it is evident that so wide a definition does not exclude the ordinary vegetative cells of sprouting fungi, such as yeasts, or small sclerotium like cell-aggregates of forms like Coniothecium. Morphologically considered, spores are marked by peculiarities of form, size, colour, place of origin, definiteness in number, mode of preparation, and so forth, such that they can be distinguished more or less sharply from the hyphae which produce them. The only physiological peculiarity exhibited in common by all spores is that they germinate and initiate the production of a new fungus-plant. Whether a spore results from the sexual union of two similar gametes (zygospore) or from the fertilization of an egg-cell by the protoplasm of a male organ (oospore); or is developed asexually as a motile (zoospore) or a quiescent body cut off from a hypha (conidium) or developed along its course (oidium or chlamydospore), or in its protoplasm (endospore), are matters of importance which have their uses in the classification and terminology of spores, though in many respects they are largely of academic interest.

Klebs has attemped to divide spores into three categories as follows: (I) kinospores, arising by relatively simple cell-divisions and subserving rapid dissemination and propagation, e.g. zoospores, conidia, endogonidia, stylospores, &c.; (2) paulospores, due to simple rearrangement of cell-contents, and subserving the persistence of the fungus through periods of exigency, e.g. gemmae, chlamydospores, resting-cells, cysts, &c.; (3) carpospores, produced by a more or less complex formative process, often in special fructifications, and subserving either or both multiplication and persistence, e.g. zygospores, oospores, brand-spores, aecidiospores, ascospores, basidiospores, &c. Little or nothing is gained by these definitions, however, which are especially physiological. In practice these various kinds of spores of fungi receive further special names in the separate groups, and names, more over, which will appear, to those unacquainted with the history, to have been given without any consistency or regard to general principles; nevertheless, for ordi nary purposes these names are far more useful in most cases, owing to their descriptive character, than the proposed new names, which have been only partially accepted.

Sporophores

In some of the simpler fungi the spores are not borne on or in hyphae which can be distinguished from the vege A tative parts or mycelium, but in the vast majority of cases the sporogenous hyphae either ascend free into the air or radiate into the surrounding water as distinct branches, or are grouped into special columns, cushions, layers or complex masses obviously different in colour, consistency, shape and other characters from the parts which gather up and assimilate the food-materials. The term "receptacle" sometimes applied to these spore-bearing _ hyphae is better replaced by sporophore. The sporophore is obsolete when the spore-bearing hyphae are not sharply distinct from the mycelium, simple when the constituent hyphae are isolated, and compound when the latter are conjoined. The chief distinctive characters of the sporogenous hyphae are their orientation, usually vertical; their limited apical growth; their peculiar branching, form, colour, contents, consistency; and their spore-production. According to the characters of the last, we might theoretically divide them into conidiophores, sporangiophores, gametophores, oidiophores, &c.; but since the two latter rarely occur, and more than one kind of spore or spore-case may occur on a sporophore, it is impossible to carry such a scheme fully into practice.

A simple sporophore may be merely a single short hypha, the end of which stops growing and becomes cut off as a conidium by the formation of a septum, which then splits and allows the conidium to fall. More generally the hypha below the septum grows forwards again, and repeats this process several times before the terminal conidium falls, and so a chain of conidia results, the oldest of which terminates the series (Erysiphe); when the primary branch has thus formed a basipetal series, branches may arise from below and again repeat this process, thus forming a tuft (Penicillium). Or the primary hypha y first swell at its apex, and put forth a series of short peg-like branches (sterigmata) from the increased surface thus provided, each of which develops a similar basipetal chain of conidia (Aspergillus), and various combinations of these processes result in the development of numerous varieties of exquisitely branched sporophores of this type (Botrytis, Botryosporium, Verticillium, &c.). A second type is developed as follows: the primary hypha forms a septum below its apex as before, and the terminal conidium, thus abstricted, puts out a branch at its apex, which starts as a mere point and rapidly swells to a second conidium; this repeats the process, and so on, so that we now have a chain of conidia developed in acropetal succession, the oldest being below, and, as in Penicillium, &c., branches put forth lower down may repeat the process (Hormodendron). In all these cases we may speak of simple conidiophores. The simple sporophore does not necessarily terminate in conidia, however. In Mucor, for example, the end of the primary hypha swells into a spheroidal head (sporangium), the protoplasm of which FIG. 3. - Cystopus candidus. A. a, Conidia. os, Oosphere.

b, Conidiophores. an, Antheridium.

c, Conidium emitting zooC. Formation of zoospores by spores. oospores.

d, Free zoospore. z, Free zoospores. (After De B.og, Oogonium. Bary.) (X 400.) undergoes segmentation into more or less numerous globular masses, each of which secretes an enveloping cell-wall and becomes a spore (endospore), and branched systems of sporangia may arise as before (Thamnidium). Such may be termed sporangiophores. In Sporodinia the branches give rise also to short branches, which meet and fuse their contents to form zygospores. In Peronospora, Saprolegnia, &c., the ends of the branches swell up into sporangia, which develop zoospores in their interior (zoosporangia), or their contents become oospheres, which may be fertilized by the contents of other branches (antheridia) and so form egg-cases (oogonia). Since in such cases the sporophore bears sexual cells, they may be conveniently termed gametophores.

Compound sporophores arise when any of the branched or unbranched types of spore-bearing hyphae described above ascend into the air in consort, and are more or less crowded into definite layers, cushions, columns or other complex masses. The same laws apply to the individual hyphae and their branches as to simple sporophores, and as long as the conidia, sporangia, gametes, &c., are borne on their external surfaces, it is quite consistent to speak of these as compound sporophores, &c., in the sense described, however complex they may become. Among the simplest cases are the sheet-like aggregates of sporogenous hyphae in Puccinia, Uromyces, &c., or of basidia in Exobasidium, Corticium, &c., or of asci in Exoascus, Ascocorticium, &c. In the former, where the layer is small, it is often termed a sorus, but where, as in the latter, the sporogenous layer is extensive, and spread out more or less sheet-like on the supporting tissues, it is more frequently termed a hymenium. Another simple case is that of the columnar aggregates of sporogenous hyphae in forms like Stilbum, Coremium, &c. These lead FIG. 2. - Peronospora parasilica (De Bary). Conidiophore with conidia.

us to cases where the main mass of the sporophore forms a supporting tissue of closely crowded or interwoven hyphae, the sporogenous terminal parts of the hyphae being found at the periphery or apical regions only. Here we have the cushion-like type (stroma) of Nectria and many Pyrenomycetes, the clavate "receptacle" of Clavaria, &c., passing into the complex forms met with in Sparassis, Xylaria, Polyporei, and Agaricini, &c. In these cases the compound sporophore is often termed the hymenophore, and its various parts demand special names (pileus, stipes, gills, po--es, &c.) to denote peculiarities of distribution of the hymenium owlthe surface.

Other series of modifications arise in which the tissues corresponding to the stroma invest the sporogenous hyphal ends, and thus enclose the spores, asci, basidia, &c., in a cavity. In the simplest case the stroma, after bearing its crop of conidia or oidia, develops ascogenous branches in the loosened meshes of its interior (e.g. Onygena). Another simple case is where the plane or slightly convex surface of the stroma rises at its margins and overgrows the sporogenous hyphal ends, so that the spores, asci, &c., come to lie in the depression of a cavity - e.g. Solenia, Cyphella - and even simpler cases are met with in Mortierella, where the zygospore is invested by the overgrowth of a dense mat of closely branching hyphae, and in Gymnoascus, where a loose mat of similarly barren hyphae covers in the tufts of asci as they develop.

In such examples as the above we may regard the hymenium (Solenia, Cyphella), zygospores, or asci as truly invested by later growth, but in the vast majority of cases the processes which result in the enclosure of the spores, asci, &c., in a "fructification" are much more involved, inasmuch as the latter is developed in the interior of hyphal tissues, which are by no means obviously homologous with a stroma. Thus in Penicillium, Eurotium, Erysiphe, &c., hyphal ends which are the initials of ascogenous branches, are invested by closely packed branches at an early stage of development, and the asci develop inside what has by that time become a complete investment. Whether a true sexual process precedes these processes or not does not affect the present question, the point being that the resulting spheroidal "fructification" (cleistocarp, perithecium) has a definite wall of its own not directly comparable with a stroma. In other cases (Hypomyces, Nectria) the perithecia arise on an already mature stroma, while yet more numerous examples can be given (Poronia, Hypoxylon, Claviceps, &c.) where the perithecia originate below the surface of a stroma formed long before. Similarly with the various types of conidial or oidial "fructifications," termed pycnidia, spermogonia, aecidia, &c. In the simplest of these cases - e.g. Fumago - a single mycelial cell divides by septa in all three planes until a more or less solid clump results. Then a hollow appears in the centre owing to the more rapid extension of the outer parts, and into this hollow the cells lining it put forth short sporogenous branches, from the tips of which the spores (stylospores, c nidia, spermatia) are abstricted. In a similar way are developed the oycnidia of Cicinnobolus, Pleospora, Cucurbitaria, Leptosphaeria and `thers. In other cases (Diplodia, Aecidium, &c.) conidial or oidial "fructifications" arise by a number of hyphae interweaving themselves into a knot, as if they were forming a sclerotium. The outer parts of the mass then differentiate as a wall or investment, and the interior becomes a hollow, into which hyphal ends grow and abstrict the spores. Much more complicated are the processes in a large series of "fructifications," where the mycelium first develops a densely packed mass of hyphae, all alike, in which labyrinths of cavities subsequently form by separation of hyphae in the previously homogeneous mass, and the hymenium covers the walls of these cavities and passages as with a lining layer. Meanwhile differences in consistency appear in various strata, and a dense outer protective layer (peridium), soft gelatinous layers, and so on are formed, the whole eventually attaining great complexity - e.g. puff-balls, earth-stars and various Phalloideae. Spore-Distribution. - Ordinary conidia and similarly abstricted dry spores are so minute, light and numerous that their dispersal is ensured by any current of air or water, and we also know that rats and other burrowing animals often carry them on their fur; similarly with birds, insects, slugs, worms, &c., on claws, feathers, proboscides, &c., or merely adherent to the slimy body. In addition to these accidental modes of dispersal, however, there is a series of interesting adaptations on the part of the fungus itself. Passing over the locomotor activity of zoospores (Pythium, Peronospora, Saprolegnia) we often find spores held under tension in sporangia (Pilobolus) or in asci (Peziza) until ripe, and then forcibly shot out by the sudden rupture of the sporangial wall under the pressure of liquid behind - mechanism comparable to that of a pop-gun, if we suppose air replaced by watery sap. Even a single conidium, held tense to the last moment by the elastic cell-wall, may be thus shot forward by a spurt of liquid under pressure in the hypha abstricting it (e.g. Empusa), and similarly with basidiospores (Coprinus, Agaricus, &c.). A more complicated case is illustrated by Sphaerobolus, where the entire mass of spores, enclosed in its own peridium, is suddenly shot up into the air like a bomb from a mortar by the elastic retroversion of a peculiar layer which, up to the last moment, surrounded the bomb, and then suddenly splits above, turns inside out, and drives the former as a projectile from a gun. Gelatinous or mucilaginous degenerations of cell-walls are frequently employed in the interests of spore dispersal. The mucilage surrounding endospores of Mucor, conidia of Empusa, &c., serves to gum the spore to animals. Such gums are formed abundantly in pycnidia, and, absorbing water, swell and carry out the spores in long tendrils, which emerge for days and dry as they reach the air, the glued spores gradually being set free by rain, wind, &c. In oidial chains (Sclerotinia) a minute double wedge of wall-substance arises in the middle lamella between each pair of contiguous oidia, and by its enlargement splits the separating lamella. These disjunctors serve as points of application for the elastic push of the swelling spore-ends, and as the connecting outer lamella of cell-wall suddenly gives way, the spores are jerked asunder. In many cases the slimy masses of spermatia (Uredineae), conidia (Claviceps), basidiospores (Phallus, Coprinus), &c., emit more or less powerful odours, which attract flies or other insects, and it has been shown that bees carry the flagrant oidia of Sclerotinia to the stigma of Vaccinium and infect it, and that flies carry away the foetid spores of Phallus, just as pollen is dispersed by such insects. Whether the strong odour of trimethylamine evolved by the spores of Tilletia attracts insects is not known.

The recent observations and exceedingly ingenious experiments of Falck have shown that the sporophores of the Basidiomycetesespecially the large sporophores of such forms as Boletus, Polyporus- contain quantities of reserve combustible material which are burnt up by the active metabolism occurring when the fruit-body is ripe. By this means the temperature of the sporophore is raised and the difference between it and the surrounding air may be one of several degrees. As a result convection currents are produced in the air which are sufficient to catch the basidiospores in their fall and carry them, away from the regions of comparative atmospheric stillness near the ground, to the upper air where more powerful air-currents can bring about their wide distribution.

Classification

It has been accepted for some time now that the majority of the fungi proper fall into three main groups, the Phycomycetes, Ascomycetes and Basidiomycetes, the Schizomycetes and Myxomycetes (Mycetozoa) being considered as independent groups not coming under the true fungi.

The chief schemes of classification put forward in detail have been those of P. A. Saccardo (1882-1892), of Oskar Brefeld and Von Tavel (1892), of P. E. L. Van Tieghem (1893) and of J. Schroeter (1892). The scheme of Brefeld, which was based on the view that the Ascomycetes and Basidiomycetes were completely asexual and that these two groups had been derived from one division (Zygomycetes) of the Phycomycetes, has been very widely accepted. The recent work of the last twelve years has shown, however, that the two higher groups of fungi exhibit distinct sexuality, of either a normal or reduced type, and has also rendered very doubtful the view of the origin of these two groups from the Phycomycetes. The real difficulty of classification of the fungi lies in the polyphyletic nature of the group. There is very little doubt that the primitive fungi have been derived by degradation from the lower algae. It appears,. however, that such a degradation has occurred not only once in evolution but on several occasions, so that we have in the Phycomycetes not a series of naturally related forms, but groups. which have arisen perfectly independently of one another from various groups of the algae. It is also possible in the absence of satisfactory intermediate forms that the Ascomycetes and Basidiomycetes have also been derived from the algae independently of the Phycomycetes, and perhaps of one another.

A natural classification on these lines would obviously be very complicated, so that in the present state of our knowledge it will be best to retain the three main groups mentioned above,. bearing in mind that the Phycomycetes especially are far from being a natural group. The following gives a tabular survey of the scheme adopted in the present article: A. Phycomycetes. Alga-like fungi with unicellular thallus and well-marked sexual organs.

Class I. - Oomycetes. Mycelium usually well developed, but sometimes poor or absent. Sexual reproduction by oogonia and antheridia; asexual reproduction by zoospores or conidia.

1. Monoblepharidineae. Mycelium present, antheridia with antherozoids, oogonium with single oosphere: Monoblepharidaceae.

2. Peronosporineae. Mycelium present; antheridia but no antherozoids; oogonia with one or more oospheres: Peronosporaceae, Saprolegniaceae.

3. Chytridineae. Mycelium poorly developed or absent; oogonia and antheridia (without antherozoids) known in some cases; zoospores common: Chytridiaceae. Ancylistaceae.

Class Ii. - Zygomycetes. Mycelium well developed; sexual reproduction by zygospores; asexual reproduction by sporangia and conidia.

1. Mucorineae. Sexual reproduction as above, asexual by sporangia or conidia or both: Mucoraceae. Mortierellaceae, Chaetocladiaceae, Piptocephalidaceae.

2. Entomophthorineae. Sexual reproduction typical but with sometimes inequality of the fusing gametes (gametangia ?): Entomophthoraceae.

B. Higher Fungi. Fungi with segmental thallus; sexual reproduction sometimes with typical antheridia and oogonia (ascogonia) but usually much reduced.

Class I. - Ustilaginales. Forms with septate thallus, and reproduction by chlamydospores which on germination produce sporidia; sexuality doubtful.

Class I I. - Ascomycetes. Thallus septate; spores developed in special type of sporangium, the ascus, the number of spores being usually eight. Sexual reproduction sometimes typical, usually reduced.

Exoascineae, Saccharomycetineae, Perisporinea, Disco mycetes, Pyrenomycetes, Tuberineae, Laboulbeniineae.

CLASS III. - Basidiales. Thallus septate. Conidia (basidiospores) borne in fours on a special conidiophore, the basidium. Sexual reproduction always much reduced.

1. Uredineae. Life-history in some cases very complex and with well-marked sexual process and alternation of generations, in others much reduced; basidium (promycelium) derived usually from a thick-walled spore (teleutospore).

2. Basidiomycetes. Life-history always very simple, no wellmarked alternation of generations; basidium borne directly on the mycelium.

(A) Protobasidiomycetes. Basidia septate.

Auriculariaceae, Pilacreaceae, Tremellinaceae.

(B) Autobasidiomycetes. Basidia non-septate. Hymenomycetes, Gasteromycetes.

A. Phycomycetes. - MOSt of the recent work of importance in this group deals with the cytology of sexual reproduction and of spore-formation, and the effect of external conditions on the production of reproductive organs.

Monoblepharidaceae consists of a very small group of aquatic forms living on fallen twigs in ponds and ditches. Only one genus, Monoblepharis, can certainly be placed here, though a somewhat similar genus. Myrioblepharis, with a peculiar multiciliate zoospore like that of Vaucheria, is provisionally placed in the same group. Monoblepharis was first described by Cornu in 1871, but from that time until 1895 when Roland Thaxter described several species from America the genus was completely lost sight of. Monoblepharis has oogonia with single oospheres and antheridia developing a few amoeboid uniciliate antherozoids; these creep to the opening of the oogonium and then swim in. The resemblance between this genus and Oedogonium among the algae is very striking, as is also that of Myrioblepharis and Vaucheria. Peronosporaceae are a group of endophytic parasites - about ioo species - of great importance as comprising the agents of "damping off" disease (Pythium), vine-mildew (Plasmopara), potato disease (Phytophthora), onion-mildew (Peronospora). Pythium is a semiaquatic form attacking seedlings which are too plentifully supplied with water; its hyphae penetrate the cell-walls and rapidly destroy the watery tissues of the living plant; then the fungus lives in the dead remains. When the free ends of the hyphae emerge again into the air they swell up into spherical bodies which may either fall off and behave as conidia, each putting out a germ-tube and infecting the host; or the germ-tube itself swells up into a zoosporangium which develops a number of zoospores. In the rotting tissues branches of the older mycelium similarly swell up and form antheridia and oogonia (fig. 4). The contents of the antheridium are not set free, but that organ penetrates the oogonium by means of a narrow outgrowth, the fertilizing tube, and a male nucleus then passes over into the single oosphere, which at first multinucleate becomes uninucleate before fertilization. Pythium is of interest as illustrating the dependence of zoospore-formation on conditions and the indeterminate nature of conidia. The other genera are more purely parasitic; the mycelium usually sends haustoria into the cells of the host and puts out branched, aerial conidiophores through the stomata, the branches of which abstrict numerous "conidia"; these either germinate directly or their contents break up into zoospores (fig. 5). The development of the "conidia" as true conidial spores or as zoosporangia may occur in one and the same species (Cystopus candidus, Phytophthora infestans) as in Pythium described above; in other cases the direct conidial germination is characteristic of genera - e.g. Peronospora; while others emit zoospores - e.g. Plasmopara, &c. In Cystopus (Albugo) the "conidia" are abstricted in basipetal chain-like series from the ends of hyphae which come to the surface in tufts and break through the epidermis as white pustules. Each "conidium" contains numerous nuclei and is really a zoosporangium, as after dispersal it breaks up into a number of zoospores. The Peronosporaceae reproduce themselves sexually by means of antheridia and oogonia as described in Pythium. In Cystopus Bliti the oosphere contains numerous nuclei, and all the male nuclei from the antheridium pass into it, the male and female nuclei then fusing in pairs. We thus have a process of "multiple fertilization"; the oosphere really represents a large From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 4. - Fertilization of the Peronosporeae. (After Wager, X 666.) I, Peronospora parasitica. Young tube (a) of the antheridium multinucleate oogonium (og) which introduces the male and antheridium (an). nucleus.

2, Albugo candida. Oogonium 3, The same. Fertilized egg with the central uninucleate cell (o) surrounded by the oosphere and the fertilizing periplasm (p).

number of undifferentiated gametes and has been termed a coenogamete. Between Cystopus Bliti on the one hand and Pythium de Baryanum on the other a number of cytologically intermediate forms are known. The oospore on germination usually gives origin A ?°. k FIG. 5. - Phytophthora infestans. Fungus of Potato Disease.

A, B, Section of Leaf of Potato F, G, H, J, Further development with sporangiophores of Phy- of the sporangia.

tophthora infestans passing K, Germination of the zoospores through the stomata D, on formed in the sporangia. the under surface of the leaf. L, M, N, Fertilization of the E, Sporangia. oogonium and development of the oospore in Peronospora. to a zoosporangium, but may form directly a germ tube which infects the host.

Saprolegniaceae are aquatic forms found growing usually on dead insects lying in water but occasionally on living fish (e.g. the salmon disease associated with Saprolegnia ferax). The chief genera are Saprolegnia, Achlya, Pythiopsis, Dictyuchus, A planes. Motile zoospores which escape from the zoosporangium are present except in Aplanes. The sexual reproduction shows all transitions between forms which are normally sexual, like the Peronosporaceae, to forms in which no antheridium is developed and the oospheres develop parthenogenetically. The oogonia, unlike the Peronosporaceae, contain more than one oosphere. Klebs has shown that the development of zoosporangia or of oogonia and pollinodia respectively in Saprolegnia is dependent on the external conditions; so long as a continued stream of suitable food-material is ensured the mycelium grows on without forming reproductive organs, but directly the supplies of nitrogenous and carbonaceous food fall below a certain degree of concentration sporangia are developed. Further reduction of the supplies of food effects the formation of oogonia. This explains the sequence of events in the case of a Saprolegnia-mycelium radiating from a dead fly in water. Those parts nearest the fly and best supplied develop barren hyphae only; in a zone at the periphery, where the products of putrefaction dissolved in the water form a dilute but easily accessible supply, the zoosporangia are developed in abundance; oogonia, however, are only formed in the depths of this radiating mycelium, where the supplies of available food materials are least abundant.

Chytridineae

These parasitic and minute, chiefly aquatic, forms may be looked upon as degenerate Oomycetes, since a sexual process and feeble unicellular mycelium occur in some; or they may be regarded as series of primitive forms leading up to higher members. There is no means of deciding the question. They are usually included in Oomycetes, but their simple structure, minute size, usually uniciliate zoospores, and their negative characters would justify their retention as a separate group. It contains less than 200 species, chiefly parasitic on or in algae and other water-plants or animals, of various kinds, or in other fungi, seedlings, pollen and higher plants. They are often devoid of hyphae, or put forth fine protoplasmic filaments into the cells of their hosts. After absorbing the cell-contents of the latter, which it does in a few hours or days, the fungus puts out a sporangium, the contents of which break up into numerous minute swarm-spores, usually one-ciliate, rarely two-ciliate. Any one of these soon comes to rest on a host-cell, and either pierces it and empties its contents into its cavity, where the further development occurs (Olpidium), or merely sends in delicate protoplasmic filaments (Rhizophydium) or a short hyphal tube of, at most, two or three cells, which acts as a haustorium, the further development taking place outside the cell-wall of the host (Chytridium). In some cases resting spores are formed inside the host (Chytridium), and give rise to zoosporangia on germination. In a few species a sexual process is described, consisting in the conjugation of similar cells (Zygochytrium) or the union of two dissimilar ones (Polyphagus). In the development of distinct antheridial and oogonial cells the allied Ancylistineae show close alliances to Pythium and the Oomycetes. On the other hand, the uniciliate zoospores of Polyphagus have slightly amoeboid movements, and in this and the pseudopodium-like nature of the protoplasmic processes, such forms suggest resemblances to the Myxomycetes. Opinions differ as to whether the Chytridineae are degraded or primitive forms, and the group still needs critical revision. Many new forms will doubtless be discovered, as they are rarely collected on account of their minuteness. Some forms cause damping off of seedlings - e.g. Olpidium Brassicae; others discoloured spots and even tumour-like swellings - e.g. Synchytium Scabiosae, S. Succisae, Urophlyctis, &c., on higher plants. Analogies have been pointed out between Chytridiaceae and unicellular algae, such as Chlorosphaeraceae, Protococcaceae, "Palmellaceae," &c., some of which are parasitic, and suggestions may be entertained as to possible origin from such algae.

The Zygomycetes, of which about 200 species are described, are especially important from a theoretical standpoint, since they furnished the series whence Brefeld derived the vast majority of the fungi. They are characterized especially by the zygospores, but the asexual organs (sporangia) exhibit interesting series of changes, beginning with the typical sporangium of Mucor containing numerous endospores, passing to cases where, as in Thamnidium, these are accompanied with more numerous small sporangia (sporangioles) containing few spores, and thence to Chaetocladium and Piptocephalis, where the sporangioles form but one spore and fall and germinate as a whole; that is to say, the monosporous sporangium has become a conidium, and Brefeld regarded these and similar series of changes as explaining the relation of ascus to conidium in higher fungi. According to his view, the ascus is in effect the sporangium with several spores, the conidium the sporangiole with but one spore, and that not loose but fused with the sporangiole wall. On this basis, with other interesting morphological comparisons, Brefeld erected his hypothesis, now untenable, that the Ascomycetes and Basidiomycetes diverge from the Zygomycetes, the former having particularly specialized the ascus (sporangial) mode of reproduction, the latter having specialized the conidial (indehiscent one-spored sporangiole) mode. In addition to sporangia and the conidial spores referred to, some Mucorini show a peculiar mode of vegetative reproduction by means of gemmae or chlamydospores - i.e. short segments of the hyphae become stored with fatty reserves and act as spores. The gemmae formed on submerged Mucors may bud like a yeast, and even bring about alcoholic fermentation in a saccharine solution.

The segments of the hyphae in this group usually contain several nuclei. At the time of sporangial formation the protoplasm with numerous nuclei streams into the swollen end of the sporangiophore and there becomes cut off by a cell-wall to form the sporangium. The protoplasm then becomes cut up by a series of clefts into a number of smaller and smaller pieces which are unicellular in Pilobolus, multicellular in Sporodinia. These then become surrounded by a cell-wall and form the spores. This mode of sporeformation is totally different from that in the ascus; hence one of the difficulties of the acceptance of Brefeld's view of the homology of ascus and sporangium. The cytology of zygospore-formation is not known in detail; the so-called gametes which fuse are multinucleate and are no doubt of the nature of gametangia. The fate of these nuclei is doubtful, probably they fuse in pairs (fig. 6).

Blakeslee has lately made some very important observations of the Zygomycetes. It is well known that while in some forms, e.g. Spordinia, zygospores are easily obtained, in others, e.g. most species of Mucor, they are very erratic in their appearance. This has now been explained by Blakeslee, who finds that the Mucorinae can be divided into two groups, termed homothallic and heterothallic respectively. In the first group zygospores can arise by the union of branches from the same mycelium and so can be produced by the growth from a single spore; this group includes Spordinia grandis, Spinellus fusiger, some species of Mucor, &c. The majority of forms, however, fall into the heterothallic group, in which the association of branches from two mycelia different in I nature is necessary for the 2, formation of zygospores.

These structures cannot 3, then be produced from the product of a single spore nor even from the thalli derived from any two spores. The two kinds of 4, thalli Blakeslee considers to have a differentiation 5, of the nature of sex and he distinguishes them as (+) and (-) forms; the former being usually distinguished by a somewhat greater luxuriance of growth. The classification of the Mucorini depends on the prevalence and characters of the conidia, and of the sporangia and zygospores - e.g. the presence or absence of a columella in the former, the formation of an investment round the latter. Most genera are saprophytes, but some - Chaetocladium, Piptocephalis - are parasites on other Mucorini, and one or two are associated casually with the rotting of tomatoes and other fruits, bulbs, &c., the fleshy parts of which are rapidly destroyed if once the hyphae gain entrance. Even more important is the question of mycosis in man and other animals, referred to species of Mucor, and investigated by Lucet and Costantin. Klebs has concluded that transpiration is the important factor in determining the formation of sporangia, while zygotedevelopment depends on totally different conditions; these results have been called in question by Falck.

The Entomophthoraceae contain three genera, Empusa, Entomophthora and Basidiobolus. The two first genera consist of forms which are parasitic on insects. Empusa Muscae causes the wellknown epidemic in house-flies during the autumn; the dead, affected flies are often found attached to the window surrounded by a white halo of conidia. B. ranarum is found in the alimentary canal of the frog and growing on its excrement. In these three genera the conidia are cast off with a jerk somewhat in the same way as the sporangium of Pilobolus. From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 6. - Mucor Mucedo. Different stages in the formation and germination of the zygospore. (After Brefeld, I-4 X225, 5 X circa 60, from v. Tavel, Pilze.) Two conjugating branches in contact. Septation of the conjugating cells (a) from the suspensors (b).

More advanced stage, the conjugating cells (a) are still distinct from one another; the warty thickenings of their walls have commenced to form.

Ripe zygospore (b) between the suspensors (a).

Germinating zygospore with a germtube bearing a sporangium.

B. Higher Fungi. - Now that Brefeld's view of the origin of these forms from the Zygomycetes has been overthrown, the relationship of the higher and lower forms of fungi is left in obscurity. The term Eumycetes is sometimes applied to this group to distinguish them from the Phycomycetes, but as the same name is also applied to the fungi as a whole to differentiate them from the Mycetozoa and Bacteria, the term had best be dropped. The Higher Fungi fall into three groups: the Ustilaginales, of doubtful position, and the two very sharply marked groups Basidiales and A scomycetes. I. Ustilaginales. - This includes two families Ustilaginaceae (smuts) and Tilletiaceae (bunts). The bunts and smuts which damage our grain and fodder plants comprise about 400 species of internal parasites, found in all countries on herbaceous plants, and especially on Monocotyledons. They are remarkable for their dark spores developed in gall-like excrescences on the leaves, stems, &c., or in the fruits of the host. The discovery of the yeast-conidia of these fungi, and their thorough investigation by Brefeld, have thrown new lights on the group, as also have the results elucidating the nature of the ordinary dark spores - smuts, bunt, &c. - which by their mode of origin and development are chlamydospores. When the latter germinate a slender "promycelium" is put out; in Ustilago and its allies this is transversely septate, and bears lateral conidia (sporidia); in Tilletia and its allies non-septate, and bears a terminal tuft of conidia (sporidia) (fig. 7). Brefeld regarded the promycelium as a kind of basidium, bearing lateral or terminal conidia (comparable to basidiospores), but since the number of basidiospores is not fixed, and the basidium has not yet assumed very definite morphological characters, Brefeld termed the group Hemibasidii, and regarded them as a halfway stage in the evolution of the true Basidiomycetes from Ph co Y Y mycetes, the Tilletia type leading to the true basidium (Autobasidium), the Ustilago type to the proto pm basidium, with lateral spores; but this p m view is based on very poor evidence, so that it is best to place these forms ?p ,c;,::, as a separate group, the Ustilaginales. The yeast-conidia, which bud off from the conidia or their resulting mycelium when sown in nutrient solutions, are developed in successive crops by budding exactly as in the yeast plant, but they cannot ferment sugar solutions. It is the rapid spread of these yeast-conidia in manure and soil waters which makes it so difficult to get rid of smuts, &c., in the fields, and they, like the ordinary conidia, readily infect the seedling wheat, oats, barley or other cereals. Infection in these cases occurs in the seedling at the place where root and shoot meet, and the infecting hypha having entered the plant goes on living in it and growing up with it as if it had no parasitic action at all. When the flowers form, however, the mycelium sends hyphae into the young ovaries and rapidly replaces the stores of sugar and starch, &c., which would have gone to make the grain, by the soot-like mass of spores so well known as smut, &c. These spores adhere to the grain, and unless destroyed, by "steeping" or other treatment, are sown with it, and again produce sporidia and yeast-conidia which infect the seedlings. In other species the infection occurs through the style of the flower, but the fungus after reaching the ovule develops no further during that year but remains dormant in the embryo of the seed. On germination, however, the fungus behaves in the same way as one which has entered in the seedling stage. The cytology of these forms is very little known; Dangeard states that there is a fusion of two nuclei in the chlamydospore, but this requires confirmation. Apart from this observation there is no other trace of sexuality in the group.

A scomycetes. - This, except in the case of a few ? of the simpler forms, is a very sharply marked group characterized by a special type of sporangium, the ascus. In the development of the ascus we find two nuclei at the base which fuse together to form the single nucleus of the young ascus. The single nucleus divides by three successive divisions to form eight nuclei lying free in the protoplasm of the ascus. Then by a special method, described first by Harper, a mass of protoplasm is cut out round each nucleus; thus eight uninucleate ascospores are formed by free-cell formation. The protoplasm remaining over is termed epiplasm and often contains glycogen (fig. 8). In some cases nuclear division is carried further before spore-formation occurs, and the number of spores is then 16, 32 and 64, &c.; in a few cases the number of spores is less than eight by abortion of some of the eight nuclei. The ascus is thus one of the most sharply characterized structures among the fungi.

In some forms we find definite male and female sexual organs (Sphaerotheca, Pyronema, &c.), in others the antheridium is abortive or absent, but the ascogonium (oogonium) is still present and the female nuclei fuse in pairs (Lachnea stercorea, Humaria granulata, Ascobolus furfuraceus); while in other forms ascogonium and antheridium are both absent and fusion occurs between vegetative nuclei (Humaria rutilans, and probably the majority of other forms). In other cases the sexual fusion is apparently absent altogether, as in Exoascus. In the first case (fig. 9) we have a true sexual process, while in the second and third cases we have a reduced sexual process in which the fusion of other nuclei has replaced the fusion of the normal male and female nuclei. It is to be noted that all the forms exhibit the fusion of nuclei in the ascus, so that those with the normal or reduced sexual process described above have two nuclear fusions in their lifehistory. The advantage or significance of the second (ascus) fusion is not clearly understood.

The group of the Hemiasci was founded by Brefeld to include forms which were supposed to be a connecting link between Phycomycetes and Ascomycetes. As mentioned before, the connexion between these two groups is very doubtful, and the derivation of the ascus from an ordinary sporangium of the Zygomycetes cannot be accepted. The majority of the forms which were formerly included in this group have been shown to be either true Phycomycetes (like A scoidea) or true Ascomycetes (like Thelebolus). Eremascus and Dipodascus, which are often placed among the Hemiasci, possibly do not belong to the Ascomycetes series at all.

Exoascaceae are a small group of doubtful extent here used to include Exoascus, Taphrina, Ascorticium and Endomyces. The I, Oogonium (og) with the an5, Fertilized oogonium sur theridial branch (az) applied rounded by two layers of to its surface. hyphae derived from the 2, Separation of antheridium stalk-cell (st).

(an). 6, The multicellular ascogonium 3, Passage of the antheridial derived by division from the nucleus towards that of the oogonium; the terminal cell oogonium. with the two nuclei (as) 4, Union of the nuclei. gives rise to the ascus.

mycelium is very much reduced in extent. The asci are borne directly on the mycelium and are therefore fully exposed, being devoid from the beginning of any investment. The Taphrineae, which include Exoascus and Taphrina, are important parasites - e.g. pocket-plums and witches' brooms on birches, &c., are due to their action (fig. io). Exoascus and Ascorticium present interesting parallels to Exobasidium and Corticium among the Basidiomycetes.

Saccharomycetaceae include the well-known yeasts which belong mainly to the genus Saccharomyces. They are characterized by their unicellular nature, their power of rapid budding, their capacity for fermenting various sugars, and their power of forming endogenous From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 9. - Sphaerotheca Castagnei. Fertilization and Development of the Perithecium. (After Harper.) From Vine's Students' Text Book of Botany, by permission of Swan Sonnenschein & Co.

FIG. 7. - Germinating resting-gonidia. A, of Ustilago receptaculorum; of Tilletia Caries (X 460).

sp, The gonidium.

pm, The promycelium.

d, The sporidia: in B the sporidia have coalesced in pairs at v. From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 8. - Development of the Ascus.

A - C, Pyronema confluens. (After Harper.) Young ascus of Boudiera with eight spores. (After Claussen.) D, spores. The sporangium with its endogenous spores has been compared with an ascus, and on these grounds the group is placed among the Ascomycetes - a very doubtful association. The group has attained an importance of late even beyond that to which it was brought by Pasteur's researches on alcoholic fermentation, chiefly owing to the exact results of the investigations of Hansen, who first applied the methods of pure cultures to the study of these organisms, and showed that many of the inconsistencies hitherto existing in the literature were due to the coexistence in the cultures of several species or races of yeasts morphologically almost indistinguishable, but physiologically very different. About fifty species of Saccharomyces are described more or less completely, but since many of these cannot be distinguished by the microscope, and some have been found to develop physiological races or varieties under special conditions of - ?u growth, the limits are still far too ill-defined for complete ep botanical treatment of the genus.

A typical yeast is able to develop b new cells by budding when submerged in a saccharine solution, and to ferment the sugar - i.e. so to break up its molecules that, apart from small quantities used for its own substance, masses of it out of all proportion to the mass of yeast used become resolved into other bodies, such as carbon dioxide and alcohol, the process requiring little or no oxygen. Brefeld regards the budding process as the formation of conidia. Under other conditions, of which the temperature is an important one, the nucleus in the yeast-cell divides, and each daughter-nucleus again, and four spores are formed in the mother cell, a process obviously comparable to the typical development of ascospores in an ascus. Under yet other conditions the quiescent yeast-cells floating on the surface of the fermented liquor grow out into elongated sausage-shaped or cylindrical cells and branching cell-series, which mat together into mycelium-like veils. At the bottom of the fermented liquor the cells often obtain fatty contents and thick walls, and behave as resting cells (chlamydospores). The characters employed by experts for determining a species of yeast are the sum of its peculiarities as regards form and size: the shapes, colours, consistency, &c., of the colonies grown on certain definite media; the optimum temperature for spore-formation, and for the development of the "veils"; and the behaviour as regards the various sugars.

The following summary of some of the principal characteristics of half-a-dozen species will serve to show how such peculiarities can be utilized for systematic purposes: and others have shown that a ferment (zymase) can be extracted from yeast-cells which causes sugar to break up into carbon dioxide and alcohol. It has since been shown by Buchner and Albert that yeast-cells which have been killed by alcohol and ether, or with acetone, still retain the enzyme. Such material is far more active than the zymase obtained originally by Buchner from the expressed juice of yeast-cells. Thus alcoholic fermentation is brought into line with the other fermentations.

Schizosaccharomyces includes a few species in which the cells do not "bud" but become elongated and then divide transversely. In the formation of sporangia two cells fuse together by means of outgrowths, in a manner very similar to that of Spirogyra; sometimes, however, the wall between two cells merely breaks down. The fused cell becomes a sporangium, and in it eight spores are developed. In certain cases single cells develop parthenogenetically, without fusion, each cell producing, however, only four spores. In Zygosaccharomyces described by Barker (1901) we have a form of the usual sprouting type, but here again there is a fusion of two cells to form a sporangium.

Species.

Optimum Temperature for

Characters of

Sugars Fermented and

Products, &c.

Spores.

Veils.

Fermentation.

Cells.

Spores.

S. cereviseae I..

300

200-28°

High

Rounded

Globoid

Inverts maltose and sac-

S. Pastorianus I..

27°-5°

26°-28°

Low

Rounded

Globoid

charose and form alcohol

S. ellipsoideus..

25°

33°-34°

Low

Rounded

Globoid

4-6 vol. %.

°°

Ditto, and evolves a fra-

S. anomalus.

28-31

?

High

Elliptical

Hat-shaped

grant ether.

S. Ludwigii

300-31°

?

?

Elongated

Globoid

Will not invert maltose.

S. merrtbranaefaciens.

30°

?

High

Elongated

Globoid

1 Inverts neither maltose nor

saccharose.

Cytology

The study of the nucleus of yeast-cells is rendered difficult by the presence of other deeply staining granules termed by Guillermond naetachromatic granules. These have often been mistaken for nuclei and have to be carefully distinguished by differential stains. In the process of budding the nucleus divides apparently by a process of direct division. In the formation of spores the nucleus of the cell divides, the protoplasm collects round the nuclei to form the spores by free-cell formation; the protoplasm (epiplasm) not used in this process becomes disorganized. A fusion of nuclei was originally described by Jansens and Leblanc, but it was observed neither by Wager nor Guillermond and is probably absent. In Schizosaccharomyces and Zygosaccharomyces, however, we have a fusion of nuclei in connexion with the conjugation of cells which precedes sporangium-formation. The theory may be put forward that the ordinary forms have been derived from sexual forms like Schizosaccharomyces and Zygosaccharomyces by a loss of sexuality, the sporangium being formed parthenogenetically without any nuclear fusion. This suggests a possible relationship to Eremascus, which can only doubtfully be placed in the Ascomycetes (vide supra). Carpoascomycetes. - The other divisions of the Ascomycetes may be distinguished as Carpoascomycetes because they do not bear the asci free on the mycelium but enclosed in definite fruit bodies or ascocarps. The ascocarps can be distinguished into two portions, a mass of sterile or vegetative hyphae forming the main mass of the fruit bod y, and surrounding the fertile ascogenous hyphae which bear at their ends the asci. When the ascogonium (female organ) is present the ascogenous hyphae arise from it, with or without its previous fusion with an antheridium. In other cases the ascogenous hyphae arise directly from the vegetative hyphae. In connexion with this condition of reduction a fusion of nuclei has been observed in Humaria rutilans and is probably of frequent occurrence. The asci may be derived from the terminal cell of the branches of the ascogenous hyphae, but usually they are derived from the penultimate cell, the tip curving over to form the so-called crozier. By this means the ascus cell is brought uppermost, and after the fusion of the two nuclei it develops enormously and produces the ascospores. The ascospores escape from the asci in various ways, sometimes by a special ejaculation-mechanism. The Ascomycetes, at least the Carpoascomycetes, exhibit a well-marked alternation of sexual and asexual generations. The ordinary mycelium is the gametophyte since it hears the ascogonia and aritheridia when present; the cqe Two questions of great theoretical importance have been raised over and over again in connexion with yeasts, namely, (I) the morphological one as to whether yeasts are merely degraded forms of higher fungi, as would seem implied by their tendency to form elongated, hypha-like cells in the veils, and their development of "ascospores" as well as by the wide occurrence of yeast-like "sprouting forms" in other fungi (e.g. Mucor, Exoasci, Ustilagineae, higher Ascomycetes and Basidiomycetes); and (2) the question as to the physiological nature and meaning of fermentation. With regard to the first question no satisfactory proof has as yet been given that Saccharomycetes are derivable by culture from any higher form, the recent statements to that effect not having been confirmed. At the same time there are strong grounds for insisting on the resemblances between Endomyces, a hyphal fungus bearing yeast-like asci, and such a form as Saccharomyces anomalus. Concerning the second question, the recent investigations of Buchner ascogenous hyphae with their asci represent the sporophyte since they are derived from the fertilized ascogonium. The matter is complicated by the apogamous transition from gametophyte to sporophyte in the absence of the ascogonium; also by the fact that there are normally two fusions in the life-history as mentioned earlier. If there are two fusions one would expect two reductions, and Harper has suggested that the division of the nuclei into eight in the ascus, instead of into four spores as in most reduction processes, is associated with a double reduction process in the ascus. Miss Fraser in Humaria rutilans finds two reductions: a normal synaptic reduction in the first nuclear division of the ascus, and a peculiar reduction division termed brachymeiosis in the third ascus division.

Various types of ascocarp are characteristic of the different divisions of the Carpoascomycetes: the cleistothecium, apothecium and perithecium.

From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. lo. - Taphrina Pruni. Transverse section through the epidermis of an infected plum. Four ripe asci, a i, a2, with eight spores, a 3, a4, with yeast-like conidia abstricted from the spores. (After Sadebeck, X600.) st, Stalk-cells of the asci.

m, Filaments of the mycelium cut transversely.

cut, Cuticle.

ep, Epidermis.

Perisporineae

This includes two chief families, Erysiphaceae and Perisporiaceae. They are characterized by an ascocarp without any opening to the exterior, the ascospores being set free by the decay or rupture of the ascocarp wall; such a fruit-body is termed a cleistothecium (cleistocarp). The Erysiphaceae are a sharply marked group of forms which live as parasites. They form a superficial mycelium on the surface of the plant, the hyphae not usually penetrating the tissues but merely sending haustoria into the epidermal cells. Only in rare cases is the mycelium intercellular. Owing to their appearance they go by the popular name of mildews. Sphaerotheca Humuli is the well known hop-mildew, Sphaerotheca MorsUvae is the gooseberry mildefv, the recent advent of which has led to special legislation in Great Britain to prevent its spreading, as when rampant it makes the culture of gooseberries impossible. Erysiphe, Uncinula and Phyllactinia are other well-known genera. The form of the fruit body, the difference and the nature of special outgrowths upon it - the appendages - are characteristic of the various genera. Besides peritheca the members of the Erysiphaceae possess conidia borne in simple chains. De Bary brought forward very strong evidence for the origin of the ascocarp in Sphaerotheca and Erysiphe by a sexual process, but Harper in 1895 was the first to prove conclusively, by the observation of the nuclear fusion, that there was a definite fertilization in Sphaerotheca Humuli by the fusion of a male (antheridial) nucleus with a female, ascogonial (oogonial) nucleus. Since then Harper has shown that the same process occurs in Erysiphe and Phyllactinia. The Perisporiaceae are saprophytic forms, the two chief genera being Aspergillus and Penicillium. The blue-green mould P. crustaceum and the green mould A. herbariorium (= Eurotium herbariorum) are extraordinarily widely distributed, moulds being found on almost any food-material which is exposed to the air. They have characteristic conidiophores bearing numerous conidia, and also cleistothecia which are spherical in form and yellowish in colour. The latter arise from the crown of a spirally coiled archicarp (bearing an ascogonium at its end) and a straight antheridium. Vegetative hyphae then grow up and surround these and enclose them in a continuous sheath of plectenchyma (fig. II). It has lately been shown by Fraser and Chambers that in Eurotium both io FIG. i i. - Development of Eurotium repens. (After De Bary.) A, Small portion of mycelium D, The perithecium. with conidiophore (c), and E, F, Sections of young periyoung archicarp (as). thecia.

B, The spiral archicarp (as), w, Parietal cells.

with the antheridium (p). f, Pseudo-parenchyma. D, The same, beginning to be as, Ascogonium.

surrounded by the hyphae G, An ascus.

forming the perithecium wall. H, An ascospore.

ascogonium and antheridium contain a number of nuclei (i.e. are coenogametes), but that the antheridium disorganizes without passing its contents into the ascogonium. There is apparently a reduced sexual process by the fusion of the ascogonial (female) nuclei in pairs. Aspergillus Oryzae plays an important part in saccharifying the starch of rice, maize, &c., by means of the abundant diastase it secretes, and, in symbiosis with a yeast which ferments the sugar formed, has long been used by the Japanese for the preparation of the alcoholic liquor sake. The process has now been successfully introduced into European commerce.

Disccmycetes

Used in its widest sense this includes the Hysteriaceae, Phacidiaceae, Helvellaceae, &c. The group is characterized in general by the possession of an ascocarp which, though usually a completely closed structure during the earlier stages of development, at maturity opens out to form a bowl or saucer-shaped organ, thus completely exposing the layer of asci which forms the hymenium. Such an ascocarp goes by the name of apothecium. Owing to the shape of the fruit-body many of these forms are known as cup-fungi, the cup or apothecium often attaining a large size, sometimes several inches across (fig. 12). Functional male and female organs have been shown to exist in Pyronema and Boudiera; in Lachnea stercorea both ascogonia and antheridia a are present, but the antheridium a1 is non-functional, the ascogonial _s- - (fema l e) nuclei fusing in pairs; /'y' this is also the case' in Humaria /;' h; granulate and Ascobolus furfurs -./ '"aceus, where the antheridium is _ / /, - entirely absent. In H. rutilans, ?r, 9 however, both sexual organs are '? ,i i )1 ? ? absent and the ascogenous ?? %&_. e hyphae arise apogamously from

`a? ? '; ?'? the ordinary hyphae of the my- ?? ?` celim. In all these cases the FIG. 13. - A scobolus furfuraceus. Diagrammatic section of the fructification. (After Janczewski.) m, Mycelium.

c, Archicarp.

1, Pollinodium.

s, Ascogenous filaments.

a, Asci. _ r, p, The sterile tissue from which jthe paraphyses h spring.

ascogonium and antheridium contain numerous nuclei; they are to be looked upon as gametangia in which there is no differentiation of gametes, and since they act as single gametes they are termed coenogametes. In some forms as in Ascobolus the ascogonium is multicellular, the various cells communicating by pores in the transverse walls (fig. 13). In the Helvellaceae there is no apothecium but a large irregular fruit body which at maturity bears the asci on its surface. The development is only slightly known, but there is some evidence for believing that the fruit-body is closed in its very early stages.

The genus Peziza (in its widest sense) may be taken as the type of the group. Most of them grow on living plants or on dead vegetable remains, very often on fallen wood; a number, however, are found growing on earth which is rich in humus. The genus Sclerotinia may be mentioned here; a number of forms have been investigated by Woronin. The conidia are fragrant and are carried by bees to the stigma of the bilberry; here they germinate with the pollen and the hyphae pass with the pollen tubes down the style; the former infect the ovules and produce sclerotia, therein reducing the fruits to a mummified condition. From the sclerotia later the apothecium develops. One species, S. heteroica, is heteroecious; the ascospores infecting the leaves of Vaccinium uliginosum, while the conidia which then arise infect only Ledum palustre. This is the only case of heteroecism known in the vegetable kingdom outside the Uredineae.

Pyrenomycetes

This is an extraordinarily large and varied group of forms which mostly live parasitically or saprophytically on vegetable tissue, but a few are parasitic on insect-larvae. The group From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 12. Peziza aurantiaca. (After Krombholz, nat. size.) From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 14. - Perithecium of Podospora fimiseda in longitudinal section (After v. Tavel. X 90.) s, Asci.

a, Paraphyses.

e, Periphyses.

m, Mycelial hyphae.

is characterized by a special type of ascocarp, the perithecium. This is typically of a flask-shaped form opening with a small pore at the top. The asci live at the bottom often mixed with paraphyses, while the upper" neck "of the flask is lined with special hyphae, the periphyses, which aid in the ejection of the spores (fig. 14). The simpler forms bear the perithecia directly on the mycelium, but the more highly developed forms often bear them on a special mycelial development - the stroma, which is often of large size and special shape and colour, and of dense consistence. The cytological details of development of the perithecia are not well known; most of them appear to develop their ascogenous hyphae in an apogamous way without any connexion with an ascogonium. Besides the special ascocarps, accessory reproductive organs are known in the majority of cases in the form of conidia.

Tuberineae

These are a small group of fungi including the wellknown truffles. They are found living saprophytically (in part parasitically) underground in forests. The asci are developed in the large dense fruit bodies (cleistothecia) and the spores escape by the decay of the wall. The fruit-body is of complicated structure, but its early stages of development are not known. Many of the fruit-bodies have a pleasant flavour and are eaten under the name of truffles (Tuber brumale and other species). The exact life-history of the truffle is not known.

Laboulbeniineae are a group of about 150 species of fungi found on insects, especially beetles, and principally known from the researches of Thaxter in America. The plant is a small, dark brown, erect structure (receptacle) of a few cells; and 1-10 mm. high, attached to the insect by the lowermost end (foot), and easily mistaken for a hair or similar appendage of the insect. The receptacle ends above in appendages, each consisting of one or a few cells, some of which are the male organs, others the female organs, and others again may be barren hairs. The male organ (antheridium) consists of a few cells, the terminal one of which either abstricts from its end, or emits from its interior the non-motile spermatia, reminding us of those of the Florideae. The female organ is essentially a flask-shaped structure; the neck of the flask growing out as the trichogyne, and the belly composed of an axial carpogenic cell surrounded by investing cells, and with one cell (trichophoric) between it and the trichogyne. These three elements - trichogyne, trichophoric cell, and carpogenic cell - are regarded as the procarp. The spermatia have been shown by Thaxter to fuse with the trichogyne, after which the axial cell below (carpogenic cell) undergoes divisions, and ultimately forms asci containing ascospores, while cells investing this form a perithecium, the whole structure reminding us essentially of the fructification of a Pyrenomycete. Many modifications in details occur, and the plants may be dioecious. No injury is done to the infested insects. It has lately been shown that there is a fusion of nuclei in connexion with ascus formation, so that there can be no doubt of the position of this extraordinary group of plants among the Ascomycetes. The various cells of these organisms are connected by large pits which are traversed by thick protoplasmic threads connecting one cell with the next. In this point and in their method of fertilization theLaboulbeniineae suggest a possible relationship of Ascomycetes and the Red Algae.

Basidiales

This very large group of plants is characterized by the possession of a special type of conidiophore - the basidium, which gives its name to the group. The basidium is a unicellular or multicellular structure from which four basidiospores arise as outgrowths; it starts asa binucleate structure, but soon, like the ascus, becomes uninucleate by the fusion of the two nuclei. Then two successive nuclear divisions occur resulting in the formation of four nuclei which later migrate respectively into the four basidiospores (fig. 15). The Basidiales are further characterized by the complete loss of normal sexuality, but at some time or other in the life-history there takes place an association of two nuclei in a cell; the two nuclei are derived from separate cells or possibly in some cases are sister nuclei of the same cell. The two nuclei when once associated are termed" conjugate "nuclei, and they always divide at the same time, a half of each passing into each cell. This conjugate condition is finally brought to a close by the nuclear fusion in the basidium. Between the nuclear association and the nuclear fusion in the basidium many thousands of cell generations may be intercalated.

This nuclear association of equivalent nuclei apparently represents a reduced sexual process (like the fusion of female nuclei in Humaria granulate and of vegetative nuclei in H. rutilans, among the Ascomycetes) in which, however, the actual fusion (normally, in a sexual process, occurring immediately after association) is delayed until the formation of the basidium. During the tetrad division in the basidium nuclear reduction occurs. There is thus in all the Basidiales an alternation of generations, obscured, however, by the apogamous transition from the gametophyte to sporophyte. The sporophyte may be considered to begin at the stage of nuclear association and end with the nuclear reduction in the basidium.

Uredineae

This is a large group of about 2000 forms. They are all intercellular parasites living mostly on the leaves of higher plants. Owing to the presence of oily globules of an orange-yellow or rusty-red colour in their hyphae and spores they are termed Rust-Fungi. They are distinguished from the other fungi and the rest of the Basidiales by the great variety of the spores and the great elaboration of the life-history to be found in many cases. Five different kinds of spores may be present - teleutospores, sporidia (= basidiospores), aecidiospores, spermatia and uredospores (fig. 16). The teleutospore, with the sporidia which arise from it, is always present, and the division into genera is based chiefly on vulgaris, with a, aecidium fruits, p, peridium, and sp, spermogonia. (After Sachs.) C, Mass of uredospores (ur), with one teleutospore (t). sh, Sub-hymenial hyphae. (After De Bary.) its characters. The teleutospore puts forth on germination a fourcelled structure, the promycelium or basidium, and this bears later four sporidia or basidiospores, one on each cell. When the sporidia infect a plant the mycelium so produced gives origin to aecidiospores and spermatia; the aecidiospores on infection produce a mycelium which bears uredospores and later teleutospores. This is the lifehistory of the most complicated forms, of the so-called eu forms. In the opsis forms the uredospores are absent, the mycelium from the aecidiospores producing directly the teleutospores. In brachy and hemi the aecidiospores are absent, the mycelium from the sporidia giving origin directly to the uredospores; the former possess spermatia, in the latter they are absent. In lepto and micro forms both aecidiospores and uredospores are absent, the sporidia producing a mycelium which gives rise directly to teleutospores; in the lepto forms the teleutospores can germinate directly, in the micro forms only after a period of rest. We have thus a series showing a progressive reduction in the complexity of the life-history, the lepto and micro forms having a life-history like that of the Basidiomycetes. The eu and opsis forms may exhibit the remarkable phenomenon of heteroecism, i.e. the dependence of the fungus on two distinct host-plants for the completion of the life-history. Heteroecism is very common in this group and is now known in over one hundred and fifty species. In all cases of heteroecism the sporidia infect one host leading to the production of aecidiospores and spermatia (if present), while the aecidiospores are only able to infect another B /., f. .f'? FIG. i 6. - Puccinia graminis. A, Mass of teleutospores (t) on a leaf of couch-grass.

e, Epidermis ruptured.

b, Sub-epidermal fibres. (After De Bary.) B, Part of vertical section through leaf of Berberis From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.

FIG. 15. - Armillaria mellea. (After Ruhland.) A, Young basidium with the two primary nuclei.

B, After fusion of the two nuclei. Hypholoma appendiculatum. C, A basidium before the four nucleiderived from the secondary nucleus of the basidium have passed into the four basidiospores.

D, Passage of a nucleus through the sterigma into the basidiospore.

Species.

Teleutospores on

Aecidiospores on

Coleosporium Senecionis

Pinus

Senecio

Melampsora Rostrupi

Populus

Mecurialis

Pucciniastrum Goeppertiana

Vaccinium

Abies

Gymnosporangium Sabinae

Juniperus

Pyrus

Uromyces Pisi

Pisum, &c.

Euphorbia

Puccinia graminis

Triticum, &c.

Berberis

P. dispersa

Secale, &c.

Anchusa

P. coronata

Agrostis

Rhamnus

P. Ari-Phalaridis

Phalaris

Arum

P. Caricis

Carex

Urtica

Cronartium Ribicola

Ribes

Pinus

Chrysomyxa Rhododendri

Rhododendron

Picea

host on which the uredospores (if present) and the teleutospores are developed. A few examples are appended: Some of the Uredineae also exhibit the peculiarity of the development of biologic forms within a single morphological species, sometimes termed specialization of parasitism; this will be dealt with later under the section Physiology.

Cytology of Uredineae

The study of the nuclear behaviour of the cells of the Uredineae has thrown great light on the question of sexuality. This group like the rest of the Basidiales exhibits an association of nuclei at some point in its life-history, but unlike the case of the Basidiomycetes the point of association in the Uredineae is very well defined in all those forms which st .:_ possess aecidiospores. We find a 3 thus that in the eu and opsis forms the association of nuclei takes place at the base of the aecidium which produces the aecidiospores. There we find an association of nuclei either by the fusion of two similar cells as described by Christmann or by the migration of the nucleus of a vegetative cell into a special cell of the aecidium. After this association the nuclei continue in the conjugate condition so s that the aecidiospores, the uredospore-bearing mycelium, the uredospores and the young teleutospores all contain two paired nuclei in their cells (fig.

17). Before the teleutospore reaches maturity the nuclei fuse, and the uninucleate condition Q C then continues again until aeci dium formation. In the hemi, brachy, micro and lepto forms, which possess no aecidium, we find that the association takes place at various points in the ordinary mycelium but always A, Portion of a young aecidium. before the formation of the st, Sterile cell. uredospores in the hemi and a, Fertile cells; at a 2 the brachy forms, and before the passage of a nucleus from formation of teleutospores in the adjoining cell is seen. micro and lepto form. Whether B, Formation of the first sporethe association of nuclei in the mother-cell (sm), from the ordinary mycelium takes place basal cell (a) of one of the by the migration of a nucleus rows of spores. from one cell to another or C, A further stage in which whether two daughter nuclei from sm l the first aecidiobecome conjugate in one cell, spore (a) and the intercalary is not yet clear. The most cell (z) have arisen. reasonable interpretation of the sm2, The second spore-mother-cell. spermatia is that they are D, Ripe aecidiospore. abortive male cells. They have never been found to cause in fection, and they have not the characters of conidia; the large size of their nuclei, the reduction of their cytoplasm and the absence of reserve material and their thin cell wall all point to their being male gametes. Although in the forms without aecidia the two generations are not sharply marked off from one another, we may look up the generation with single nuclei in the cells as the gametophyte and that with conjugate nuclei as the sporophyte. The subjoined diagram will indicate the relationship of the forms.

Basidiomycetes

This group is characterized by its greatly reduced life-history as compared with that of the eu forms among the Uredineae. All the forms have the same life-history as the lepto forms of that group, so that there is no longer any trace of sexual organs. There is also a further reduction in that the basidium is not derived from a teleutospore but is borne directly on the mycelium. Formerly, before the relationship of promycelium and basidium were understood, the Uredineae were considered as quite independent of the Basidiomycetes. Later, however, these Uredineae were placed as a mere subdivision of the Basidiomycetes. Although the Uredineae clearly lead on to the Basidiomycetes, yet owing to their retaining in many cases definite traces of sexual organs they are clearly a more primitive group. Their marked parasitic habit also separates them off, so that they are best included with the Basidiomycetes in a larger cohort which may be called Basidiales. Most of Basidiomycetes are characterized by the large sporophore on which the basidia with its basidiospores are borne.

It must be clearly borne in mind that though the Basidiomycetes show no traces of differ entiated sexual organs yet, like the micro and lepto forms of the Uredineae, they still show (in the association of nuclei and later fusion of From Annals of Botany, by permission of the Clarendon Press. nuclei in the basFIG. 18.

idium), a reduced fertilization which denotes their derivation, through the Uredineae, from more typically sexual forms. No one has yet t.-ade out in any form the exact way in which the association of nuclei tr -.-es place in the group. The mycelium is always found to contain conjugate nuclei before the formation of basidia, but the point at which the conjugate condition arises seems very variable. Miss Nichols fi -ids that it occurs very soon after the germination of the spore in Cc sinus, but no fusion of cells or migration of nuclei was to be observed.

Protobasidiomycetes

This, by far the smaller division of Basidiomycetes, includes those forms which have a septate basidium. There are three families - Auriculariaceae, Pilacreaceae and Tremellinaceae.

B p C v 1 A" FIG. 19. - Amanita muscaria. A, The young plant. a, The annulus, or remnant of B, The mature plant. [plant. velum partiale. C, Longitudinal section of mature v, Remains of volva or velum p, The pileus. universale. g, The gills. s, The stalk.

The first named contains a small number of forms with the basidium divided like the promycelium of the Uredineae. They are characterized by their gelatinous consistence and large size of their sporophore. Hirneola (Auricularia) Auricula-Judae is the well-known Jew's Ear, so named from the resemblance of the sporophore to a human ear.

The Pilacreaceae are a family found by Brefeld to contain the genus Pilacre. P. Petersii has a transversely divided basidium as in Auriculariaceae, but the basidia are surrounded with a peridium-like sheath. The Tremellinaceae are characterized by the possession of basidia which are divided by two vertical walls at right angles to one another. From each of the four segments in the case of Tremella a long outgrowth arises which reaches to the surface of the hymenium From Strasburger's Lehrbuch der Bolanik, by permission of Gustav Fischer.

FIG. 17. - P hragmidium Violaceum. (After Blackman.) uredospores _ l ?

mycelium ircdospores otachY' ar Mycelium aecidi'spores teleutospores (young) - mycelium SporoNtyte with conjugate nuclei GametohyEe with single nuclei teleutospores ?(mature) 8a ?; sporida ?m celium erm $ fertile cells Y sp (abortaitviae) (of aecidium) fertilized cells (of aecidium) and bears the basidiospores. In Dacryomyces only two outgrowths and two spores are produced.

Autobasidiomycetes

In this by far the larger division of the Basidiomycetes the basidia are undivided and the four basidiospores are borne on short sterigmata nearly always at the apex of the basidium. The group may be divided into two main divisions, Hymenomycetes and Gasteromycetes. Hymenomycetes are a very large group containing over 11,000 species, most of which live in soil rich in humus or on fallen wood or stems, a few only being parasites. In the simplest forms (e.g. Exobasidium) the basidia are borne directly on the ordinary mycelium, but in the majority of cases the basidia are found developed in layers (hymenium) on special sporophores of characteristic form in the various groups. In these sporophores (such as the well-known toadstools and mushrooms where the ordinary vegetative mycelium is underground) we have structures specially developed for bearing the basidiospores and protecting them from rain, &c., and for the distribution of the spores - see earlier part of article on distribution of spores (figs. 19 and 20). The underground mycelium in many cases spreads wider and wider each year, often in a circular manner, and the sporophores springing from it appear in the form of a ring - the so called fairy rings. Ar- millaria melleus and Polyporus annosus are examples of parasitic forms which attack and destroy living trees, while Merulius lacryg s ! g ?. / mans is the well-known zv " dry rot" fungus.

FIG. 20. - A garicus mucidus. Portion Gasteromycetes are of hymenium ! X350). s, Sporidia; st, characterized by having sterigmata; r. sterile cells; c, cystidium, closed sporophores or with operculum o. fruit-bodies which only open after the spores are ripe and then often merely by a small pore. The fruit-bodies are of very varic. as shapes, showing a differentiation into an outer peridium and an i:..ier spore-bearing mass, the gleba. The gleba is usually differentiated into a number of chambers which are lined directly by the hymenium (basidial layer), or else the chambers contain an interwoven mass of hyphae, the branches of which bear the basidia. By the breaking down of the inner tissues the spores often come to lie as a loose powdery mass in the interior of the hollow fruitbody, mixed sometimes with a capillitium. The best-known genera are Bovista, Lycoperdon (puff-ball) Scleroderma, Geaster (earth-star, q.v.). In the last-named genus the peridium is double and the outer layer becomes ruptured and spreads out in the form of star-shaped pieces; the inner layer, however, merely opens at the apex by a small pore.

The most complex members of the Gasteromycetes belong to the Phalloideae, which is sometimes placed as a distinct division of the Autobasidiomycetes. Phallus impudicus, the stink-horn, is occasionally found growing in woods in Britain. The fruit-body before it ruptures may reach the size of a hen's egg and is white in colour; from this there grows out a hollow cylindrical structure which can be distinguished at the distance of several yards by its disgusting odour. It is highly poisonous.

Physiology

The physiology of the fungi comes under the head of that of plants generally, and the works of Pfeffer, Sachs, Vines, Darwin and Klebs may be consulted for details. But we may refer generally here to certain phenomena peculiar to these plants, the life-actions of which are restricted and specialized by their peculiar dependence on organic supplies of carbon and nitrogen, so that most fungi resemble the colourless cells of higher plants in their nutrition. Like these they require water, small but indispensable quantities of salts of potassium, magnesium, sulphur and phosphorus, and supplies of carbonaceous and nitrogenous materials in different stages of complexity in the different cases. Like these, also, they respire oxygen, and are independent of light; and their various powers of growth, secretion, and general metabolism, irritability, and response to external factors show similar specific variations in both cases. It is quite a mistake to suppose that, apart from the chlorophyll function, the physiology of the fungus-cell is fundamentally different from that of ordinary plant-cells. Nevertheless, certain biological phenomena in fungi are especially pronounced, and of these the following require particular notice.

Parasatasm

Some fungi, though able to live as saprophytes, occasionally enter the body of living plants, and are thus termed facultative parasites. The occasion may be a wound (e.g. Nectria, Dasyscypha, &c.), or the enfeeblement of the tissues of the host, or invigoration of the fungus, the mycelium of which then becomes strong enough to overcome the host's resistance (Botrytis). Many fungi, however, cannot complete their life-history apart from the host-plant. Such obligate parasites may be epiphytic (Erysipheae), the mycelium remaining on the outside and at most merely sending haustoria into the epidermal cells, or endophytic (Uredineae, Ustilagineae, &c.), when the mycelium is entirely inside the organs of the host. An epiphytic fungus is not necessarily a parasite, however, as many saprophytes (moulds, &c.) germinate and develop a loose mycelium on living leaves, but only enter and destroy the tissues after the leaf has fallen; in some cases, however, these saprophytic epiphytes can do harm by intercepting light and air from the leaf (Fumago, &c.), and such cases make it difficult to draw the line between saprophytism and parasitism. Endophytic parasites may be intracellular, when the fungus or its mycelium plunges into the cells and destroys their contents directly (Olpidium, Lagenidium, Sclerotinia, &c.), but they are far more frequently intercellular, at any rate while young, the mycelium growing in the lacunae between the cells (Peronospora, Uredineae) into which it may send short (Cystopus), or long and branched (Peronospora Calotheca) haustoria, or it extends in the middle lamella (Ustilago), or even in the solid substance of the cell-wall (Botrytis). No sharp lines can be drawn, however, since many mycelia are intercellular at first and subsequently become intracellular (Ustilagineae), and the various stages doubtless depend on the degrees of resistance which the host tissues are able to offer. Similar gradations are observed in the direct effect of the parasite on the host, which may be local (Hemileia) when the mycelium never extends far from the point of infection, or general (Phytophthora) when it runs throughout the plant. Destructive parasites rapidly ruin the whole plant-body (Pythium), whereas restrained parasites only tax the host slightly, and ill effects may not be visible for a long time, or only when the fungus is epidemic (Rhytisma). A parasite may be restricted during a long incubation-period, however, and rampant and destructive later (Ustilago). The latter fact, as well as the extraordinary fastidiousness, so to speak, of parasites in their choice of hosts or of organs for attack, point to reactions on the part of the host-plant, as well as capacities on that of the parasite, which may be partly explained in the light of what we 'now know regarding enzymes and chemotropism. Some parasites attack many hosts and almost any tissue or organ (Botrytis cinerea), others are restricted to one family (Cystopus candidus) or genus (Phytophthora infestans) or even species (Pucciniastrum Padi), and it is customary to speak of rootparasites, leaf-parasites, &c., in expression of the fact that a given parasite occurs only on such organs - e.g. Dematophora necatrix on roots, Calyptospora Goeppertiana on stems, Ustilago Scabiosae in anthers, Claviceps purpurea in ovaries, &c. Associated with these relations are the specializations which parasites show in regard to the age of the host. Many parasites can enter a seedling, but are unable to attack the same host when older - e.g. Pythium, Phytophthora omnivores. Chemotropism. - Taken in conjunction with Pfeffer's beautiful discovery that certain chemicals exert a distinct attractive influence on fungus hyphae (chemotropism), and the results of Miyoshi's experimental application of it, the phenomena of enzyme-secretion throw considerable light on the processes of infection and parasitism of fungi. Pfeffer showed that certain substances in definite concentrations cause the tips of hyphae to turn towards them; other substances, though not innutritious, repel them, as also do nutritious bodies if too highly concentrated. Marshall Ward showed that the hyphae of Botrytis pierce the cell-walls of a lily by secreting a cytase and dissolving a hole through the membrane. Miyoshi then demonstrated that if Botrytis is sown in a lamella of gelatine, and this lamella is superposed on another similar one to which a chemotropic substance is added, the tips of the hyphae at once turn from the former and enter the latter. If a thin cellulose membrane is interposed between the lamellae, the hyphae nevertheless turn chemotropically from the one lamella to the other and pierce the cellulose membrane in the process. The hyphae will also dissolve their way through a lamella of collodion, paraffin, parchment paper, elder-pith, or even cork or the wing of a fly, to do which it must excrete very different enzymes. If the membrane is of some impermeable substance, like gold leaf, the hyphae cannot dissolve its way through, but the tip finds the most minute pore and traverses the barrier by means of it, as it does a stoma on a leaf, We may hence conclude that a parasitic hyphae pierces some plants or their stomata and refuses to enter others, because in the former case there are chemotropically attractive substances present which are absent from the latter, or are there replaced by repellent poisonous or protective substances such as enzymes or antitoxins.

Specialization of Parasitism

The careful investigations of recent years have shown that in several groups of fungi we cannot be content to distinguish as units morphologically different species, but we are compelled to go deeper and analyse further the species. It has been shown especially in the Uredineae and Erysiphaceae that many forms which can hardly be distinguished morphologically, or which cannot be differentiated at all by structural characters, are not reall y homogeneous but consist of a number of forms which are se se s g sharply distinguishable by their infecting power. Eriksson found, for example, that the well-known species Puccinia graminis could be split up into a number of forms which though morphologically similar were physiologically distinct. He found that the species really consisted of six distinct races, each having a more or less narrow range of grasses on which it can live. The six races he named P. graminis Secalis, Tritici, Avenae, Airae, Agrostis, Poae. The first named will grow on rye and barley but not on wheat or oat. The form Tritici is the least sharply marked and will grow on wheat, barley, rye and oat but not on the other grasses. The form Avenae will grow on oat and many grasses but not on the other three cereals mentioned. The last three forms grow only on the genera Aira, Agrostis and Poa respectively. All these forms have of course their aecidium-stage on the barberry. The terms biologic forms, biological species, physiological species, physiological races, specialized forms have all been applied to these; perhaps the term biologic forms is the most satisfactory. A similar specialization has been observed by Marshall Ward in the Puccinia parasitic on species of Bromus, and by Neger, Marchal and especially Salmon in the Erysiphaceae. In the last-named family the single morphological species Erysiphe graminis is found growing on the cereals, barley, oat, wheat, rye and a number of wild grasses (such as Poa, Bromus, Dactylis). On each of these host-plants the fungus has become specialized so that the form on barley cannot infect the other three cereals or the wild grasses and so on. Just as the uredospores and aecidiospores both show these specialized characters in the case of Puccinia graminis so we find that both the conidia and ascospores of E. graminis show this phenomenon. Salmon has further shown in investigating the relation of E. graminis to various species of the genus, Bromus, that certain species may act as "bridging species," enabling the transfer of a biologic form to a host-plant which it cannot normally infect. Thus the biologic form on B. racemosus cannot infect B. commutatus. If, however, conidia from B. racemosus are sown on B. hordaceus, the conidia which develop on that plant are now able to infect B. commutatus; thus B. hordaceus acts as a bridging species. Salmon also found that injury of a leaf by mechanical means, by heat, by anaesthetics, &c., would affect the immunity of the plant and allow infection by conidia which was not able to enter a normal leaf. The effect of the abnormal conditions is probably to stop the production of, or weaken or destroy the protective enzymes or antitoxins, the presence of which normally confers immunity on the leaf.

Symbiosis

The remarkable case of life in common first observed in lichens, where a fungus and an alga unite to form a compound organism - the lichen - totally different from either, has now been proved to be universal in these plants, and lichens are in all cases merely algae enmeshed in the interwoven hyphae of fungi (see Lichens). This dualism, where the one constituent (alga) furnishes carbohydrates, and the other (fungus) ensures a supply of mineral matters, shade and moisture, has been termed symbiosis. Since then numerous other cases of symbiosis have been demonstrated. Many trees are found to have their smaller roots invaded by fungi and deformed by their action, but so far from these being injurious, experiments go to show that this mycorhiza (fungus-root) is necessary for the well-being of the tree. This is also the case with numerous other plants of moors and woodlands - e.g. Ericaceae, Pyrolaceae, Gentianaceae, Orchidaceae, ferns, &c. Recent experiments have shown that the difficulties of getting orchid seeds to germinate are due to the absence of the necessary fungus, which must be in readiness to infect the young seedling immediately it emerges from the seed. The well-known failures with rhododendrons, heaths, &c., in ordinary garden soils are also explained by the need of the fungus-infected. peat for their roots. The role of the fungus appears to be to supply materials from the leaf-mould around, in forms which ordinary root-hairs are incapable of providing for the plant; in return the latter supports the fungus at slight expense from its abundant stores of reserve materials. Numerous other cases of symbiosis have been discovered among the fungi of fermentation, of which those between Aspergillus and yeast in sake manufacture, and between yeasts and bacteria in kephir and in the ginger-beer plant are best worked out. For cases of symbiosis see Bacteriology.

Authorities. - General: Engler and Prantl, Die natiirlichen Pflanzenfamilien, i. Teil (1892 onwards); Zopf, Die Pilze (Breslau, 1890); De Bary, Comparative Morphology of Fungi, &c. (Oxford, 1887); von Tafel, Vergleichende Morphologie der Pilze (Jena, 1892); Brefeld, Ureters. aus dem Gesamtgebiete der Mykologie, Heft i. 13 (1872-1905); Lotsy, Vortrdge fiber botanische Stammesgeschichte (Jena, 1907). Distribution, &c.: Cooke, Introduction to the Study of Fungi (London, 1895); Felix in Zeitschr. d. deutsch. geologisch. Gesellsch. (1894-1896); Staub, Sitzungsber. d. bot. Sec. d. Kgl. ungarischen naturwiss. Gesellsch. zu Budapest (1897). Anatomy, &c.: Bommer, "Sclerotes et cordons myceliens," Mem. de l'Acad. Roy. de Belg. (1894); Mangin, "Observ. sur la membrane des mucorinees," Journ. de Bot. (1899); Zimmermann, Die Morph. and Physiologie des Pflanzenzellkernes (Jena, 1896); Wisselingh, "Microchem. Unters. uber die Zellwande d. Fungi," Pringsh. Jahrb. B. 31, p. 619 (1898); Istvanffvi, "Unters. uber die phys. Anat. der Pilze," Prings. Jahrb. (1896). Spore Distribution: Fulton, "Dispersal of the Spores of Fungi by Insects," Ann. Bot. (1889); Falck, "Die Sporenverbreitung bei den Basidiomyceten," Beitr. zur Biol. d. Pflanzen, ix. (1904). Spores and Sporophores: Zopf, Die Pilze; also the works of von Tafel and Brefeld. Classification: van Tieghem, Journ. de bot. p. 77 (1893), and the works of Brefeld, Engler and Prantl, von Tafel, Saccardo and Lotsy already cited. Oomycetes : Wager, "On the Fertilization of Peronospora parasi.tica," Ann. Bot. vol. xiv. (1900); Stevens, "The Compound Oosphere of Albugo Bliti," Bot. Gaz. vol. 28 (1899); "Gametogenesis and Fertilization in Albugo," ibid. vol. 32 (1901); Miyake, "The Fertilization of Pythium de Baryanum," Ann. of Bot. vol. xv. (1901); Trow, "On Fertilization in the Saprolegnieae," Ann. of Bot. vol. xviii. (1904); Thaxter, "New and Peculiar Aquatic Fungi," Bot. Gaz. vol. 20 (1895); Lagerheim, "Unters. fiber die Monoblepharideae," Bih. Svenska Vet. Akad. Handlingar, 25. Afd. iii. (1900); Woronin, "Beitrag zur Kenntnis der Monoblepharideen," Mem. de l'Acad. Imp. d. Sc. de St-Petersbourg, 8 ser. vol. 16 (1902). Zygomycetes: Harper, "Cell-division in Sporangia and Asci," Ann. Bot. vol. xiii. (1899); Klebs, Die Bedingungen der Fortpflanzung, &c. (Jena, 1896), and "Zur Physiologie der Fortpflanzung" Prings. Jahr. (1898 and 1899), "Ober Sporodinia grandis," Bot. Zeit. (1902); Falck, "Die Bedingungen der Zygotenbildung bei Sporodinia grandis," Cohn's Beitr. z. Biol. d. Pflanzen, Bd. 8 (1902); Gruber "Verhalten der Zellkerne in den Zygosporen von Sporodinia grandis," Ber. d. deutschen bot. Ges. Bd. 19 (1901); Blakeslee, "Sexual Reproduction in the Mucorineae," Proc. Am. Acad. (1904); "Zygospore germination in the Mucorineae," Annales mycologici (1906). Ustilagineae: Plowright, British Uredineae and Ustilagineae (London, 1889); Massee, British Fungi (Phycomycetes and Ustilagineae) (London, 1891); Brefeld, Unters. aus dem Gesamtgeb. der Mykol. Hefte xi. and xii.; and Falck, "Die Bluteninfektion bei den Brandpilzen," ibid. Heft xiii. 1905; Dangeard, "La Reproduction sexuelle des Ustilaginees," C.R., Oct. 9, 1893 Maire, "Recherches cytologiques et taxonomiques sur les Basidiomyceten," Annexe au Bull. de la Soc. Mycol. de France (1902). Saccharomycetaceae: Jorgensen, The Micro-organisms of Fermentation (1899); Barker, Ann. of Bot. vol. xiv. (1901); "On Sporeformation among the Saccharomycetes," Journ. of the Fed. Institute of Brewing, vol. 8 (1902); Guillermond, Recherches cytologiques sur les levures (Paris, 1902); Hansen, Centralbl. f. Bakt. u. Parasitenp. Abt. ii. Bd. 12 (1904). Exoascaceae: Giesenhagen, "Taphrina, Exoascus, Magnusiella" (complete literature given), Bot. Zeit. Bd. 7 (1901). Erysiphaceae: Harper, "Die Entwicklung des Perithecium bei Sphaerotheca castagnei," Ber. d. deut. bot. Ges. (1896); "Sexual Reproduction and the Organization of the Nucleus in certain Mildews," Publ. Carnegie Institution (Washington, 1906); Blackman & Fraser, "Fertilization in Sphaerotheca," Ann. of Bot. (1905). Perisporiaceae: Brefeld, Untersuchungen aus dem Gesamtgeb. der Mykol. Heft pp (1891); Fraser and Chamber, Annales mycologici (1907). Discomycetes: Harper, "- fiber das Verhalten der Kerne bei Ascomyceten," Jahr. f. wiss. Bot. Bd. 29 (1890); "Sexual Reproduction in Pyronema confluens," Ann. of Bot. 14 (1900); Claussen, "Zur Entw. der Ascomyceten," Boudiera, Bot. Zeit. Bd. 63 (1905); Dangeard, "Sur le Pyronema confluens," Le Botaniste, 9 serie (1903) (and numerous papers in same journal earlier and later); Ramlow, "Zur Entwick. von Thelebolus stercoren," Bot. Zeit. (1906); Woronin, "Ober die Sclerotienkrankheit der Vaccineen Beeren," Mem. de l'Acad. Imp. des Sciences de St-Petersbourg, 7 serie, 36 (1888); Dittrich, "Zur Entwickelungsgeschichte der Helvellineen," Cohn's Beitr. z. Biol. d. Pflanzen (1892). Pyrenomycetes: Fisch, "Beitr. z. Entwickelungsgeschichte einiger Ascomyceten," Bot. Zeit. (1882); Frank, "tTber einige neue u. weniger bekannte Pflanzkrankh.," Landw. Jahrb. Bd. 12 (1883); Ward, "Onygena equina, a horn-destroying fungus," Phil. Trans. vol. 191 (1899); Dawson, "On the Biology of Poroniapunctata," Ann. of Bot. 14 (1900). Tuberineae: Buchholtz, "Zur Morphologie u. Systematik der Fungi hypogaei," Ann. Mycol. Bd. i (1903); Fischer in Engler and Prantl, Die natiirlichen Pflanzenfamilien (1896). Laboulbeniineae: Thaxter, "Monograph of the Laboulbeniaceae," Mem. Amer. Acad. of Arts and Sciences, vol. 12 (1895). Uredineae: Eriksson and Henning, Die Getreideroste (Stockholm, 1896); Eriksson, Botan. Gaz. vol. 25 (1896); "On the Vegetative Life of some Uredineae," Ann. of Bot. (1905); Klebahn, Die wirtwechselnden Rostpilze (Berlin, 1904); Sapin-Trouffy, "Recherches histologiques sur la famine des Uredinees," Le Botaniste (1896-1897); Blackman, "On the Fertilization, Alternation of Generations and General Cytology of the Uredineae," Ann. of Bot. vol. 18 (1904); Blackman and Fraser, "Further Studies on the Sexuality of Uredineae," Ann. of Bot. vol. 20 (1906); Christman, "Sexual Reproduction of Rusts," Ann. of Bot. vol. 20 (1906); Ward, "The Brooms and their Rust Fungus," Ann. of Bot. vol. 15 (1901). Basidiomycetes: Dangeard, "La Reprod. sexuelle des Basidiomycetes," Le Botaniste (1894 and 1900); Maire, "Recherches cytologiques et taxonomiques sur les Basidiomycetes," Annexe du Bull. de la Soc. Mycol. de France (1902); Moller, "Protobasidiomyceten," Schimper's Mitt. aus den Tropen, Heft 8 (Jena, 1895) Nichols, "The Nature and Origin of the Binucleated Cells in certain Basidiomycetes," Trans. Wisconsin Acad. of Sciences, vol. 15 (1905); Wager, "The Sexuality of the Fungi," Ann. of Bot. 13 (1899); Woronin, "Exobasidium Vaccinii," Verh. Naturf. Ges. zu Freiburg, Bd. 4 (1867). Fermentation: Buchner, "Gahrung ohne Hefezellen," Bot. Zeit. Bd. 18 (1898); Albert, Cent. f. Bakt. Bd. 17 (1901); Green, The Soluble Ferments and Fermentation (Cambridge, 1899). Parasitism: " On some Relations between Host and Parasite," Proc. Roy. Soc. vol. 47 (1890); "A Lily Disease," Ann. of Botany, vol. 2 (1888); Eriksson & Hennings, Die Getreideroste (vide supra); Ward, "On the Question of Predisposition and Immunity in Plants," Proc. Cambridge Phil. Soc. vol. I 1 (1902); also Annals of Bot. vol. 16 (1902) and vol. 19 (1905); Neger, "Beitr. z. Biol. d. Erysipheen" Flora, Bde. 88 and 90 (1901-1902); Salmon, "Cultural Experiments with ` Biologic Forms ' of the Erysiphaceae," Phil. Trans. (1904); "On Erysiphe graminis and its adaptative parasitism within the genus, Bromus," Ann. Mycol. vol. it (1904), also Ann. of Bot. vol. 19 (1905). Symbiosis: Ward, "The Ginger-Beer Plant," Phil. Trans. Roy. Soc. (1892); "Symbiosis," Ann. of Bot. 13 (1899); Shalk, "Der Sinn der Mykorrhizenbildung," Jahrb. f. wiss. Bot. Bd. 34 (1900); Bernard, "On some Different Cases of Germination," Gardener's Chronicle (1900); Pierce, Publ. Univ. California (1900). (H. M. W.; V. H. B.)


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Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

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See also fungi

Contents

Translingual

Etymology

Latin fungus 'mushroom'

Proper noun

Singular
Fungi

Plural
-

Fungi

  1. (taxonomy) Regnum Fungi, a taxonomic kingdom (regnum), within domain Eukaryota - the mushrooms and funguses - over 100,000 species of organisms that are similar to plants but do not contain chlorophyll

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Wikispecies

Up to date as of January 23, 2010

From Wikispecies

Xerocomus chrysenteron

Taxonavigation

Main Page
Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Fungi
Phylum: Ascomycota - Basidiomycota - Chytridiomycota - Glomeromycota - Hyphochytriomycota - Labirinthulomycota - Myxomycota - Oomycota - Zygomycota - Anamorphic fungi

Vernacular names

Afrikaans: Swam
Alemannisch: Schwümm / Schwimm
አማርኛ: Սունկ
Anglo-Saxon: Swamm
العربية: فطر
Asturianu: Fungos
Bahasa Indonesia: Jamur
Bosanski: Gljive
Brezhoneg: Foue
Български: Гъби
Català: Fongs
Česky: Houby
Corsu: funghi
Српски / Srpski: Печурке=Гљиве
Dansk: Svampe
Deutsch: Pilze
Eesti: Seened
Ελληνικά: Μύκητες
English: Fungus
Español: Hongo / Fungi / Seta
Esperanto: Fungoj
Euskara: Honto
فارسی: قارچ‌ها
Føroyskt: Soppar
Français: Champignons
Gaeilge: Fungas
Galego: Fungos
한국어: 균계
Հայերեն: Սնկեր
Hrvatski: Gljive
Interlingua: Fungos
Íslenska: Sveppir
Italiano: Funghi
עברית: פטריות
Kaszëbsczi: Grzëbë
Latina: fungi
Latviešu: Sēnes
Lietuvių: Grybai
Magyar: Gombák
Македонски: Габи
Nederlands: Schimmels
日本語: 菌界
‪Norsk (bokmål)‬: Sopper
Occitan: Campairòls
Polski: Grzyby
Português: Fungos
Română: Ciuperci
Runa Simi: K'allampa
Русский: Грибы
Slovenčina: Huby, Hríby
Suomi: Sienet
Svenska: Svampar
Tagalog: Pungay
Türkçe: Mantarlar
Українська: Гриби
Vèneto: Fonghi
Walon: tchampion
ייִדיש: שוואָמען
中文: 真菌界
Wikimedia Commons For more multimedia, look at Fungi on Wikimedia Commons.







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