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Cacti
Fossil range: 35-0 Ma
Late Paleogene - Recent
Ferocactus pilosus (Mexican Lime Cactus) growing south of Saltillo, Coahuila, northeast Mexico
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Caryophyllales
Family: Cactaceae
Juss.
Subfamilies

See also taxonomy of the Cactaceae

A cactus (plural: cacti or cactuses) is any member of the plant family Cactaceae, native to the Americas (with one exception, Rhipsalis baccifera, which is native to parts of the Old World). They are often used as ornamental plants, and some are also crop plants for fodder, forage, fruits, cochineal, and other uses. Numerous species have been used since ancient times by indigenous peoples for their psychedelic effects. Cactuses are part of the plant order Caryophyllales, which also includes members like beets, gypsophila, spinach, amaranth, tumbleweeds, carnations, rhubarb, buckwheat, plumbago, bougainvillea, chickweed and knotgrass.

Cacti are unusual and distinctive plants, which are adapted to extremely arid and/or semi-arid hot environments, as well as tropical environments as epiphytes or hemi-epiphytes [1][2][3]. They show a wide range of anatomical and physiological features which conserve water. Their stems have adapted to become photosynthetic and succulent, while the leaves have become the spines for which cacti are well known.

Cacti come in a wide range of shapes and sizes. The tallest is Pachycereus pringlei, with a maximum recorded height of 19.2 m,[4] and the smallest is Blossfeldia liliputiana, only about 1 cm diameter at maturity.[5] Cactus flowers are large, and like the spines and branches arise from areoles. Many cactus species are night blooming, as they are pollinated by nocturnal insects or small animals, principally moths and bats. Cacti range in size from small and globular to tall and columnar.

Contents

Description

Closeup image of a cactus flower (Echinopsis spachiana) showing large number of stamens.
Closeup look of a cactus perianth.

Cacti are perennial and grow as trees, shrubs, or vines. Most species are terrestrial, but there are also many epiphytic species, especially in the tribes Rhipsalideae and Hylocereeae. In most species, except for the sub-family Pereskioideae (see image), the leaves are greatly or entirely reduced. The leaves may also be tiny and deciduous as can be seen on new shoots of Opuntia. Spines found in the cacti are actually modified leaves; the stems (the green "pads" of many cacti) have also evolved to photosynthesize. The flowers, mostly radially symmetrical and bisexual, bloom either by day or by night, depending on the species. Their shape varies from tube-like through bell-like to wheel-shaped, and their size from 0.2 to 15–30 centimetres. Most of them have numerous sepals (from 5 to 50 or more), and change form from outside to inside, from bracts to petals. They have stamens in great numbers (from 50 to 1,500, rarely fewer). Nearly all species of cacti have a bitter mucilaginous sap contained within them. The berry-like fruits may contain few to many (3,000), seeds, which can be between 0.4 and 12 mm long.[6]

The life of a cactus is seldom longer than 300 years[citation needed], but may be as short as 25 years, (although these flower as early as their second year). The Saguaro cactus (Carnegiea gigantea) grows to a height of up to 15 metres (the record is 17 metres 67 cm), but in its first ten years, it grows only 10 centimetres. The "mother-in-law's cushion" (Echinocactus grusonii) reaches a height of 2.5 metres and a diameter of 1 metre and – at least on the Canaries – is already capable of flowering after 6 years. The diameter of cactus flowers ranges from 5 to 30 cm; the colors are often conspicuous and spectacular.

The cactus family is endemic to the Americas with one exception, Rhipsalis baccifera; this species has a pantropical distribution, occurring in the Old World tropical Africa, Madagascar and Sri Lanka as well as in tropical America. This plant is thought to be a relatively recent colonist in the Old World (within the last few thousand years), probably carried as seeds in the digestive tracts of migratory birds. Many other cacti have become naturalized to similar environments in other parts of the world after being introduced by people, e.g. Australia, Hawaii, and the Mediterranean region. The Tehuacán Valley of Mexico has one of the richest occurrences of cacti in the world.[7] Species diversity decreases as one travels north; hundreds of species can be found in areas of Mexico, dozens of species are found in the Sonora and Mojave deserts of the southwestern U.S., and only several species are found in the eastern plains and dry valleys of Montana and Alberta.

Cacti are believed to have evolved in the last 30 to 40 million years[citation needed]. Long ago, the Americas were joined to the other continents, but separated due to continental drift. Unique species in the New World must have developed after the continents had moved apart or began developing just prior to the separation. Significant distance between the continents was only achieved in around the last 50 million years. This may explain why cacti are so rare in Africa as the continents had already separated when cacti evolved. Many succulent plants in both the Old and New World bear a striking resemblance to cacti, and are often called "cactus" in common usage.

Adaptations to dry environment

Some environments, such as deserts, semi-deserts, and dry steppes, receive little water in the form of precipitation. Plants that inhabit these dry areas are known as xerophytes, and many of them are succulents, with thick or reduced, "succulent", leaves. Apart from a few exceptions (for example, the genus Pereskia) all cacti are succulent plants. Like other succulents, cacti have a range of specific adaptations that enable them to survive in these environments.

Pereskia grandifolia: Pereskia is a weakly succulent genus, which also possesses leaves, and is believed to be very similar to the ancestor of all cacti.
Barrel Cactus growing on a cliff in the Mojave Desert. These cacti can reach up to six feet tall in some cases.
Organ Pipe cactus in Arizona
Many species of cactus have long, sharp spines.

Cacti have never lost their leaves completely[citation needed]; they have only reduced the size so that they reduce the surface area through which water can be lost by transpiration. In some species the leaves are still remarkably large and ordinary while in other species they have become microscopic but they still contain the stomata, xylem and phloem. Certain cactus species have also developed ephemeral or deciduous leaves, which are leaves that last for a short period of time when the stem is still in its early stages of development. A good example is Opuntia ficus-indica, better known as the prickly pear. Cacti have also developed spines which allow less water to evaporate through transpiration by shading the plant, and defend the cactus against water-seeking animals. The spines grow from specialized structures called areoles, homologous to the nodes on other plants. Very few members of the family have leaves, and when present these are usually rudimentary and soon fall off; they are typically awl-shaped and only 1–3 mm. long. Two genera, Pereskia and Pereskiopsis, do however retain large, non-succulent leaves 5–25 cm. long, and non-succulent stems. Pereskia has now been determined to be the ancestral genus from which all other cacti evolved.[8] Enlarged stems carry out photosynthesis and store water. Unlike many other succulents, the stem is the only part of a true cactus where this takes place. Much like many other plants that have waxy coatings on their leaves, cacti often have a waxy coating on their stems to prevent water loss and potentially repel water from their stems.

The bodies of many cacti have become thickened during the course of evolution, and form water-retentive tissue and in many cases assume the optimal shape of a sphere or cylinder (combining highest possible volume with lowest possible surface area). By reducing its surface area, the body of the plant is also protected against excessive sunlight.

Saguaro cactus in Arizona, USA. This species is well known from Western films.
A fishhook barrel cactus in Arizona, USA.

Most cacti have a short growing season and long dormancy. For example, a fully-grown Saguaro cactus (Carnegiea gigantea) can absorb up to 3,000 litres of water in ten days. This is helped by the ability to form new roots quickly. Two hours after rain following a relatively long drought, root formation begins in response to the moisture. Apart from a few exceptions, an extensively ramified root system is formed, which spreads out immediately beneath the surface. The salt concentration in the root cells is relatively high[citation needed], so that when moisture is encountered, water can immediately be absorbed in the greatest possible quantity.

But the plant body itself is also capable of absorbing moisture (through the epidermis and the thorns), which for plants that are exposed to moisture almost entirely or indeed in some cases solely, in the form of fog, is of the greatest importance for sustaining life.

Most cacti have very shallow roots that can spread out widely close to the surface of the ground to collect water, an adaptation to infrequent rains; in one examination, a young Saguaro only 12 cm. tall had a root system covering an area 2 meters in diameter, but with no roots more than 10 cm. deep.[9] The larger columnar cacti also develop a taproot, primarily for anchoring but also to reach deeper water supplies and mineral nutrients.[9]

One feature distinguishes the cacti from all other plants: cacti possess areoles, as they are known. The areole appears like a cushion with a diameter of up to 15 mm. and is formed by two opposing buds in the angles of a leaf[citation needed]. From the upper bud develops either a blossom or a side shoot, from the lower bud develop thorns. The two buds of the areoles can lie very close together, but they can also sometimes be separated by several centimeters.

Like other succulents in the families of the Crassulaceae, Agavaceae (agaves), Euphorbiaceae (euphorbias), Liliaceae (lilies), Orchidaceae (orchids) and Vitaceae (vines), cacti reduce water loss through transpiration by Crassulacean acid metabolism.[9] Here, transpiration does not take place during the day at the same time as photosynthesis, but at night. The plant stores the carbon dioxide chemically linked to malic acid until the daytime. During the day the stomata are closed and the plant releases the stored CO2 and uses it for photosynthesis. Because transpiration takes place during the cool humid night hours, water loss through transpiration is significantly reduced.

Reproductive ecology

Blooming Echinopsis. The sweet-smelling flower opens towards evening and dies the following morning.

Some cactus flowers form long tubes (up to 30 centimetres) so that only moths can reach the nectar and therefore pollinate the blossoms. There are also specializations for bats, humming birds and particular species of bees. The duration of flowering is very variable. Many flowers, for example those of Selenicereus grandiflorus (Queen of the Night) are only fully open for two hours at night. Other cacti flower for a whole week. Most cacti are self-incompatible, and thus require a pollinator. A few are autogamous and are able to pollinate themselves. Fraileas only open their flowers completely in exceptional circumstances; they mostly pollinate themselves or others with their flowers closed ("cleistogamy"). The flower itself has also undergone a further development: the ovary tends to become a completely protected area, protected by thorns, hairs and scales. Seed formation is very prolific, and the fruits are mostly fleshy, pleasant tasting and conspicuously coloured. Goats, birds, ants, mice and bats contribute significantly to the spreading of the seeds.

Because of the plants' high water-retention ability, detached parts of the plant can survive for long periods and are able to grow new roots anywhere on the plant body.

History

Carl Spitzweg: The Cactus Lover, c. 1856
Moche Cactus. 200 B.C. Larco Museum Collection Lima, Peru.

Among the remains of the Aztec civilization, cactus-like plants can be found in pictorial representations, sculpture and drawings, with many depictions resembling Echinocactus grusonii. Tenochtitlan (the earlier name of Mexico City) means "place of the sacred cactus." The coat of arms of Mexico to this day shows an eagle perched on a cactus while holding a snake, an image which is at the center of the Aztec origin myth.[10]

Economic exploitation of the cactus can also be traced back to the Aztecs. The North American Indians utilize the alkaloid content of several cacti species for religious ceremonies. Today, besides their use as foodstuffs (jam, fruit, vegetables), their principal use is as a host for the cochineal insect, from which a red dye (carmine) is obtained which is used in Campari or high-quality lipsticks. Particularly in South America dead pillar cacti yield valuable wood for construction. Some cacti are also of pharmaceutical significance.

From the moment the early European explorers sighted them, cacti have aroused much interest: Christopher Columbus brought the first melocactus to Europe. Scientific interest in them began in the 17th century. By 1737, twenty-four species were known, which Linnaeus grouped together as the genus "Cactaceae".

From the beginning of the 20th century, interest in cacti has increased steadily. This was accompanied by a rising commercial interest, the negative consequences of which culminated in raids on their native habitats. Through the great number of cactus admirers, whether their interest is scientific or hobby-oriented, new species and varieties are even today discovered every year.

All cacti are covered by the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and many species by virtue of their inclusion in Appendix 1 are fully protected.

Some countries have a rather contradictory attitude to species protection. In Mexico for example to be caught in the act of digging up cacti carries a prison sentence, but cactus habitats are destroyed for the construction of new roads and electricity lines.

The Moche people of ancient Peru worshipped agriculture and often depicted the cactus in their art [11].

Uses

Cacti, cultivated by people worldwide, are a familiar sight as potted plants, houseplants or in ornamental gardens in warmer climates. They often form part of xeriphytic (dry) gardens in arid regions, or raised rockeries. Some countries, such as Australia, have water restrictions in many cities, so drought-resistant plants are increasing in popularity. Numerous species have entered widespread cultivation, including members of Echinopsis, Mammillaria and Cereus among others. Some, such as the Golden Barrel dekha Cactus, Echinocactus grusonii, are prominent in garden design. Cacti are commonly used for fencing material where there is a lack of either natural resources or financial means to construct a permanent fence. This is often seen in arid and warm climates, such as the Masai Mara in Kenya. This is known as a cactus fence. Cactus fences are often used by homeowners and landscape architects for home security purposes. The sharp thorns of the cactus deter unauthorized persons from entering private properties, and may prevent break-ins if planted under windows and near drainpipes. The aesthetic characteristics of some species, in conjunction with their home security qualities, makes them a considerable alternative to artificial fences and walls.

A Mexican dish, nopal salad.

As well as garden plants, many cactus species have important commercial uses, some cacti bear edible fruit, such as the prickly pear and Hylocereus, which produces Dragon fruit or Pitaya. According to Reuters, the edible cactus, or nopal, industry in Mexico is worth $150 million each year and approximately 10,000 farmers cultivate the plant.[12] Opuntia are also used as host plants for cochineal bugs in the cochineal dye industry in Central America.

The Peyote, Lophophora williamsii, is a well-known psychoactive agent used by Native Americans in the Southwest of the United States of America. Some species of Echinopsis (previously Trichocereus) also have psychoactive properties. For example, the San Pedro cactus, a common specimen found in many garden centers, is known to contain mescaline.

Etymology

Prickly Pear is among the most common type of cactus found in North America

The word cactus is derived through Latin from the Greek κάκτος kaktos, which referred to the cardoon (Cynara cardunculus). Linnaeus in 1753 applied this name generically to a genus he called Cactus, which was later reassigned as a family, Cactaceae, and subdivided into multiple genera.[13] Cactuses, the Latin plural cacti, and the uninflected plural cactus are all used in English.[14]

References

  1. ^ P.S. Nobel. 1988. Environmental Biology of Agaves and Cacti. Cambridge University Press, New York.
  2. ^ P.S. Nobel. 1994. Remarkable Agaves and Cacti. Oxford University Press, New York. 166 pp. Spanish Translation by E. García Moya. 1998. Los Incomparables Agaves y Cactos. Editorial Trillas, Mexico City.
  3. ^ P.S. Nobel. 2010. DESERT WISDOM/AGAVES and CACTI: CO2, Water, Climate Change. iUniverse, Bloomington, IN.
  4. ^ Salak, M. (2000). In search of the tallest cactus. Cactus and Succulent Journal 72 (3).
  5. ^ Mauseth Cactus research: Blossfeldia liliputiana
  6. ^ http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10141 Description of the Family in the Flora of North America.
  7. ^ "Mexico: Tehuacán-Cuicatlán Biosphere Reserve." (PDF). http://www.parkswatch.org/parkprofiles/pdf/tcbr_eng.pdf. 
  8. ^ How did cacti evolve?
  9. ^ a b c Dalhousie University: Biology of Cacti
  10. ^ http://aztecs.mrdonn.org/place.html
  11. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
  12. ^ http://www.reuters.com/article/oddlyEnoughNews/idUSN2G28324120070219
  13. ^ Oxford English Dictionary, s.v. "cactus", http://dictionary.oed.com/cgi/entry/50030958.
  14. ^ Merriam-Webster's Online Dictionary, s.v. "cactus", http://www.merriam-webster.com/dictionary/cactus.

External links

Cholla cactus in bloom at night in the Mojave Desert.

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

CACTUS. This word, applied in the form of KaKros by the ancient Greeks to some prickly plant, was adopted by Linnaeus as the name of a group of curious succulent or fleshy-stemmed plants, most of them prickly and leafless, some of which produce beautiful flowers, and are now so popular in our gardens that the name has become familiar. As applied by Linnaeus, the name Cactus is almost conterminous with what is now regarded as the natural order Cactaceae, which embraces several modern genera. It is one of the few Linnaean generic terms which have been entirely set aside by the names adopted for the modern divisions of the group.

The Cacti may be described in general terms as plants having a woody axis, overlaid with thick masses of cellular tissue forming the fleshy stems. These are extremely various in character and form, being globose, cylindrical, columnar or flattened into leafy expansions or thick joint-like divisions, the surface being either ribbed like a melon, or developed into nipple-like protuberances, or variously angular, but in the greater number of the species furnished copiously with tufts of horny spines, some of which are exceedingly keen and powerful. These tufts show the position of buds, of which, however, comparatively few are developed. The stems are in most cases leafless, using the term in a popular sense; the leaves, if present at all, being generally reduced to minute scales. In one genus, however, Peireskia, the stems are less succulent, and the leaves, though rather fleshy, are developed in the usual form. The flowers are frequently large and showy, and are generally attractive from their high colouring. In one group, represented by Cereus, they consist of a tube, more or less elongated, on the outer surface of which, towards the base, are developed small and at first inconspicuous scales, which gradually 0000 FIG. I. - Prickly Pear (Opuntia vulgaris). I, Flower reduced; 2, Same in vertical section; 3, Flattened branch much reduced; 4, Horizontal plan of arrangement of flower.

increase in size upwards, and at length become crowded, numerous and petaloid, forming a funnel-shaped blossom, the beauty of which is much enhanced by the multitude of conspicuous stamens which with the pistil occupy the centre. In another group, represented by Opuntia (fig. I), the flowers are rotate, that is to say, the long tube is replaced by a very short one. At the base of the tube, in both groups, the ovary becomes developed into a fleshy (often edible) fruit, that produced by the Opuntia being known as the prickly pear or Indian fig.

The principal modern genera are grouped by the differences in the flower - tube just explained. Those with long - tubed flowers comprise the genera Melocactus, Mammillaria, Echinocactus, Cereus, Pilocereus, Echinopsis, Phyllocactus, Epiphyllum, &c.; while those with short-tubed flowers are Rhipsalis, Opuntia, Peireskia, and one or two of minor importance. Cactaceae belong almost entirely to the New World; but some of the Opuntias have been so long distributed over certain parts of Europe, especially on the shores of the Mediterranean and the volcanic soil of Italy, that they appear in some places to have taken possession of the soil, and to be distinguished with difficulty from the aboriginal vegetation. The habitats which they affect are the hot, dry regions of tropical America, the aridity of which they are enabled to withstand in consequence of the thickness of their skin and the paucity of evaporating pores or stomata with which they are furnished, - these conditions not permitting the moisture they contain to be carried off too rapidly; the thick fleshy stems and branches contain a store of water. The succulent fruits are not only edible but agreeable, and in fevers are freely administered as a cooling drink. The Spanish Americans plant the Opuntias around their houses, where they serve as impenetrable fences.

MELocACTus, the genus of melon-thistle or Turk's-cap cactuses, contains, according to a recent estimate, about 90 species, which inhabit chiefly the West Indies, Mexico and Brazil, a few extending into New Granada. The typical species, M. communis, forms a succulent mass of roundish or ovate form, from I ft. to 2 ft. high, the surface divided into numerous furrows like the ribs of a melon, with projecting angles, which are set with a regular series of stellated spines - each bundle consisting of about five larger spines, accompanied by smaller but sharp bristles - and the tip of the plant being surmounted by a cylindrical crown 3 to 5 in. high, composed of reddish-brown, needle-like bristles, closely packed with cottony wool. At the summit of this crown the small rosy-pink flowers are produced, half protruding from the mass of wool, and these are succeeded by small red berries. These strange plants usually grow in rocky places with little or no earth to support them; and it is said that in times of drought the cattle resort to them to allay their thirst, first ripping them up with their horns and tearing off the outer skin, and then devouring the moist succulent parts. The fruit, which has an agreeably acid flavour, is frequently eaten in the West Indies. The Melocacti are distinguished by the distinct cephalium or crown which bears the flowers.

Mammillaria. - This genus, which comprises nearly 300 species, mostly Mexican, with a few Brazilian and West Indian, is called nipple cactus, and consists of globular or cylindrical succulent plants, whose surface instead of being cut up into ridges with alternate furrows, as in Melocactus, is broken up into teat-like cylindrical or angular tubercles, spirally arranged, and terminating in a radiating tuft of spines which spring from a little woolly cushion. The flowers issue from between the mammillae, towards the upper part of the stem, often disposed in a zone just below the apex, and are either purple, rose-pink, white or yellow, and of moderate size. The spines are variously coloured, white and yellow tints predominating, and from the symmetrical arrangement of the areolae or tufts of spines they are very pretty objects, and are hence frequently kept in drawing-room plant cases. They grow freely in a cool greenhouse.

Echinocactus (fig. 2) is the name given to the genus bearing the popular name of hedgehog cactus. It comprises some 200 species, distributed from the south-west United States to Brazil and Chile. They have the fleshy stems characteristic of the order, these being either globose, oblong or cylindrical, and either ribbed as in Melocactus, or broken up into distinct tubercles, and most of them armed with stiff sharp pines, set in little woolly cushions occupying the place of the buds. The flowers, produced near the apex of the plant, are generally large and showy, yellow and rose being the prevailing colours. They are succeeded by succulent fruits, which are exserted, and frequently scaly or spiny, in which respects this genus differs both from Melocactus and Mammillaria, which have the fruits immersed and smooth. One of the most interesting species is the E. ingens, of which some very large plants have been from time to time imported. These large plants have from 40 to 50 ridges, on which the buds and clusters of spines are sunk at intervals, the aggregate number of the spines having been in some cases computed at upwards of 50,000 on a single plant. These spines are used by the Mexicans as toothpicks. The plants are slow growers and must have plenty of sun heat; they require sandy loam with a mixture of sand and bricks finely broken and must be kept dry in winter. CEREus. - This group bears the common name of torch thistle. It comprises about loo species, largely Mexican but scattered through South America and the West Indies. The stems are columnar or elongated, some of the latter creeping on the ground or climbing up the trunks of trees, rooting as they grow. C. giganieus, the largest and most striking species of the genus, is a native of hot, arid, desert regions of New Mexico, growing there in rocky valleys and on mountain sides, where the tall stems with their erect branches have the appearance of telegraph poles. The stems grow to a height of from 50 ft. to 60 ft., and have a diameter of from I ft. to 2 ft., often unbranched, but sometimes furnished with branches FIG. 2. - Echinocactus much reduced; the flowers are several inches in diameter.

which grow out at right angles from the main stem, and then curve upwards and continue their growth parallel to it; these stems have from twelve to twenty ribs, on which at intervals of about an inch are the buds with their thick yellow cushions, from which issue five or six large and numerous smaller spines. The fruits of this plant, which are green oval bodies from 2 to 3 in. long, contain a crimson pulp from which the Pimos and Papagos Indians prepare an excellent preserve; and they also use the ripe fruit as an article of food, gathering it by means of a forked stick attached to a long pole. The Cereuses include some of our most interesting and beautiful hothouse plants. In the allied genus Echinocereus, with 25 to 30 species in North and South America, the stems are short, branched or simple, divided into few or many ridges all armed with sharp, formidable spines. E. pectinatus produces a purplish fruit resembling a gooseberry, which is very good eating; and the fleshy part of the stem itself, which is called cabeza del viego by the Mexicans, is eaten by them as a vegetable after removing the spines.

Pilocereus, the old man cactus, forms a small genus with tallish erect, fleshy, angulate stems, on which, with the tufts of spines, are developed hair-like bodies, which, though rather coarse, bear some resemblance to the hoary locks of an old man. The plants are nearly allied to Cereus, differing chiefly in the floriferous portion developing these longer and more attenuated hair-like spines, which surround the base of the flowers and form a dense woolly head or cephalium. The most familiar species is P. senilis, a Mexican plant, which though seldom seen more than a foot or two in height in greenhouses, reaches from 20 ft. to 30 ft. in its native country.

EcHINOPSIS is another small group of species, separated by some authors from Cereus. They are dwarf, ribbed, globose or cylindrical plants; and the flowers, which are produced from the side instead of the apex of the stem, are large, and in some cases very beautiful, being remarkable for the length of the tube, which is more or less covered with bristly hairs. They are natives of Brazil, Bolivia and Chile.

Phyllocactus (fig. 3), the Leaf Cactus family, consists of about a dozen species, found in Central and tropical South America.

FIG. 3. - Branch of Phyllocactus much reduced; the flowers are 6 in. or more in diameter.

They differ from all the forms already noticed in being shrubby and epiphytal in habit, and in having the branches compressed and dilated so as to resemble thick fleshy leaves, with a strong median axis and rounded woody base. The margins of these leaf-like branches are more or less crenately notched, the notches representing buds, as do the spine-clusters in the spiny genera; and from these crenatures the large showy flowers are produced. As garden plants the Phyllocacti are amongst the most ornamental of the whole family, being of easy culture, free blooming and remarkably showy, the colour of the flowers ranging from rich crimson, through rosepink to creamy white. Cuttings strike readily in spring before growth has commenced; they should be potted in 3-in. or 4-in. pots, well drained, in loamy soil made very porous by the admixture of finely broken crocks and sand, and placed in a temperature of 600; when these pots are filled with roots they are to be shifted into larger ones, but overpotting must be avoided. During the summer they need considerable heat, all the light possible and plenty of air; in winter a temperature of 45° or 50° will be sufficient, and they must be kept tolerably dry at the root. By the spring they may have larger pots if required and should be kept in a hot and fairly moistened atmosphere; and by the end of June, when they have made new growth, they may be turned out under a south wall in the full sun, water being given only as required. In autumn they are to be returned to a cool house and wintered in a dry stove. The turning of them outdoors to ripen their growth is the surest way to obtain flowers, but they do not take on a free blooming habit until they have attained some age. They are often called Epiphyllum, which name is, however, properly restricted to the group next to be mentioned.

Epiphyllum. - This name is now restricted to two or three dwarf branching Brazilian epiphytal plants of extreme beauty, which agree with Phyllocactus in having the branches dilated into the form of fleshy leaves, but differ in having them divided into short truncate leaf-like portions, which are articulated, that is to say, provided with a joint by which they separate spontaneously; the margins are crenate or dentate, and the flowers, which are large and showy, magenta or crimson, appear at the apex of the terminal joints. In E. truncatum the flowers have a very different aspect from that of other Cacti, from the mouth of the tube being oblique and the segments all reflexed at the tip. The short separate pieces of which these plants are made up grow out of each other, so that the branches may be said to resemble leaves joined together endwise.

Rhipsalis, a genus of about 50 tropical species, mainly in Central and South America, but a few in tropical Africa and Madagascar. It is a very heterogeneous group, being fleshy-stemmed with a woody axis, the branches being angular, winged, flattened or cylindrical, and the flowers small, short-tubed, succeeded by small, round, peashaped berries. Rhipsalis Cassytha, when seen laden with its white berries, bears some resemblance to a branch of mistletoe. All the species are epiphytal in habit.

Opuntia, the prickly pear, or Indian fig cactus, is a large typical group, comprising some 150 species, found in North America, the West Indies, and warmer parts of South America, extending as far as Chile. In aspect they are very distinct from any of the other groups. They are fleshy shrubs, with rounded, woody stems, and numerous succulent branches, composed in most of the species of separate joints or parts, which are much compressed, often elliptic or suborbicular, dotted over in spiral lines with small, fleshy, caducous leaves, in the axils of which are placed the areoles or tufts of barbed or hooked spines of two forms. The flowers are mostly yellow or reddish-yellow, and are succeeded by pear-shaped or egg-shaped fruits, having a broad scar at the top, furnished on their soft, fleshy rind with tufts of small spines. The sweet, juicy fruits of 0. vulgaris and 0. Tuna are much eaten under the name of prickly pears, and are greatly esteemed for their cooling properties. Both these species are extensively cultivated for their fruit in Southern Europe, the Canaries and northern Africa; and the fruits are not unfrequently to be seen in Covent Garden Market and in the shops of the leading fruiterers of the metropolis. 0. vulgaris is hardy in the south of England.

The cochineal insect is nurtured on a species of Opuntia (0. coccinellifera), separated by some authors under the name of Nopalea, and sometimes also on 0. Tuna. Plantations of the nopal and the tuna, which are called nopaleries, are established for the purpose of rearing this insect, the Coccus Cacti, and these often contain as many as 50,000 plants. The females are placed on the plants about August, and in four months the first crop of cochineal is gathered, two more being produced in the course of the year. The native country of the insect is Mexico, and it is there more or less cultivated; but the greater part of our supply comes from New Granada and the Canary Islands.

Peireskia Aculeata, or Barbadoes gooseberry, the Cactus peireskia of Linnaeus, differs from the rest in having woody stems and leaf-bearing branches, the leaves being somewhat fleshy, but otherwise of the ordinary laminate character. The flowers are subpaniculate, white or yellowish. This species is frequently used as a stock on which to graft other Cacti. There are about a dozen species known of this genus, mainly Mexican.


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Wiktionary

Up to date as of January 15, 2010
(Redirected to cactus article)

Definition from Wiktionary, a free dictionary

Saguaro cactus (Ansel Adams, 1941)

Contents

English

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Wikipedia

Pronunciation

Etymology

Latin cactus, from Ancient Greek κάκτος (kaktos), cardoon).

Noun

Singular
cactus

Plural
cacti or cactuses

cactus (plural cacti or cactuses)

  1. (botany) Any member of the family Cactaceae, a family of flowering New World succulent plants suited to a hot, semi-desert climate.
  2. Any succulent plant with a thick fleshy stem bearing spines but no leaves, including euphorbs.

Usage notes

Wikisource
See also the 1911 Encyclopædia Britannica's article on:

The most precise definition of cactus includes only plants from the New World (the Americas) belonging to the family Cactaceae. Only one species of cactus is native to the Old World, namely the genus Pereskea is a shrubby leafy cactus that grows in western Africa. However, many African species of the family Euphorbiaceae grow in forms and shapes that resemble large species of Cactaceae. These forms are colloquially referred to as “cactus”. In general, then, any usage of the term “cactus” to plants from the Old World refers to plants in the Euphorbiaceae.

Related terms

  • cactaceous
  • cactal
  • cactoid

Derived terms

  • barrel cactus
  • beehive cactus
  • bird’s nest cactus
  • cactus cat
  • cactuslike
  • cactus wren
  • compass cactus
  • crown cactus
  • dumpling cactus
  • feather cactus
  • finger cactus
  • fishhook cactus
  • foxtail cactus
  • hedgehog cactus
  • horse crippler cactus
  • ladyfinger cactus
  • mistletoe cactus
  • nipple cactus
  • noncactus
  • old lady cactus
  • orchid cactus
  • organ pipe cactus
  • pencil cactus
  • Rainbow cactus
  • rattail cactus
  • strawberry cactus
  • thimble cactus
  • willow cactus, willow-cactus

Translations

See also

Adjective

cactus (comparative more cactus, superlative most cactus)

Positive
cactus

Comparative
more cactus

Superlative
most cactus

  1. (Australian, slang) Non-functional, broken, exhausted.
Commons
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French

Pronunciation

Noun

cactus m. (plural cactus)

  1. cactus

Latin

Etymology

From Ancient Greek κάκτος (kaktos), cardoon).

Noun

cactus (genitive cactī); m, second declension

  1. the cardoon, Cynara cardunculus

Inflection

Second declension (2).

Number Singular Plural
nominative cactus cactī
genitive cactī cactōrum
dative cactō cactīs
accusative cactum cactōs
ablative cactō cactīs
vocative cacte cactī

Simple English

Cacti
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Caryophyllales
Family: Cactaceae
Juss.

A cactus is a kind of plant. The plural of cactus can be cacti or cactuses or cactus. In science all genera of cacti (as the whole) are named Cactaceae.

Cacti first came from North America or South America. Many people like to grow cactus in pots or gardens. Now cacti have spread to many other parts of the world.

Many cacti live in dry places, such as deserts. Most cacti have and sharp thorns (stickers) and thick skin. There are many shapes and sizes of cacti. Some are short and round; others are tall and thin. Many cactus flowers are big and beautiful. Some cactus flowers bloom at night and are pollinated by moths and bats. Some cactus fruits are brightly coloured and good to eat. Goats, birds, ants, mice, bats and people eat cactus fruits.

File:Selenicereus
The flower of a Moonlight cactus.

Contents

Adaptations

An adaptation is anything that helps a living thing survive and make more of its own kind. Cactuses have many adaptations for living in places that are sometimes dry for a long time. At other times these places can get lots of rain.

Cacti can have many small, thin roots near the top of the soil. These roots take in water quickly after a rain. The same cactus may have one long, thick root called a taproot. The taproot grows deep in the soil. It can reach water when the soil on top is dry.

Cacti store water in thick stems. The stems are covered with tough skin, and the skin is covered with wax. The thick waxy skin slows down loss of water. The leaves of cacti are sharp spines (thorns, stickers). Many animals want the water inside the cactus, but the sharp spines and thick skin protect the cactus.

[[File:|thumb|left|Many species of cactus have long, sharp spines.]]

Uses

Cacti are commonly grown as houseplants. They are pretty and easy to grow. Some cacti are grown in gardens, especially in dry areas. Cactus can be used as a living fence. The wood of dead cactus is sometimes used for building.

People eat the fruit of some kinds of cactus, such as dragonfruit and prickly pear. Ciouvhiul insects also eat prickly pears. These insects produce a red coloring used in food and lipstick.

File:Yellow
Like many cactus fruits, the dragonfruit has many tiny seeds

Cactus in History

The ancient Aztecs of South America held cactus to be very important. Cactus can be found in many of their sculptures and drawings. The national coat of arms of Mexico shows an eagle, a snake, and cactus.

Christopher Columbus brought the first cactus to Europe. Scientists and gardeners became very interested in cactus.

Prickly pears were taken to Australia in the 19th century for use as a natural fence and for use in the cochineal industry. The cactus spread out of control. Now it has made 40,000 km² of land useless for farming.

From the start of the 20th century interest in cactus has grown. Every year, scientists discover new kinds of cactus. A bad effect of this bigger interest has been the digging up of many cacti from the wild, making some kinds endangered.
File:Echinocactus grusonii
Barrel cactus are often grown in gardens.

Cactus stems

A cactus does not have leaves because it lives in dry places. Leaves transpire, and this can waste water.[1] So, the cactus saves water by having no leaves. The green parts of the cactus are actually its stems. Because the stems are green, they do the photosynthesis for the cactus. They also grow prickly needles to protect the cactus from animals that want to eat it.

References

  1. Fulbright, Jeannie (2004). Exploring Creation with Botany. 1106 Meridian Plaza, Suite 220: Apologia Educational Ministries, Inc.. ISBN 1-932012-49-4. 

Websites

Simple English Wiktionary has the word meaning for:
Look up Cactaceae in Wikispecies, a directory of species
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