Asarum: Wikis

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Updated live from Wikipedia, last check: May 30, 2012 00:28 UTC (42 seconds ago)

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Asarum is a parish in Sweden, located N56 12'20; E14 50' and since 1967 part of Karlshamn municipality.

Asarum

Wild ginger leaves (Asarum caudatum)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Magnoliids
Order:	Piperales
Family:	Aristolochiaceae
Genus:	Asarum
Species
See text

Asarum (Á-sa-rum) is a genus of plants in the birthwort family Aristolochiaceae, commonly known as Wild ginger.

1 Description
2 Taxonomy
3 Species
4 See also
5 External links
6 References

Description

Asarum consists low-growing herbs , that are distributed over the north temperate zones with most species in Asia (mainly China, Japan and Vietnam), North America and one species in Europe. Biogeographically, Asarum originated in Asia

They have characteristically kidney-shaped leaves, growing from creeping rhizomes. They bear small, axillary brown or reddish flowers.

Asarum canadense is native to the forests of eastern North America. It is found from the Great Plains east to the Atlantic Coast, and from southeastern Canada south to approximately the fall line in the southeastern United States.

Asarum caudatum is found in British Columbia south through Washington and Oregon to central California, and from the Coast Range east to western Montana.

The plant is called wild ginger because the rhizome tastes and smells similar to that of ginger root, but the two are not particularly related. The root can be used as a spice, but is a potent diuretic, or urinary stimulant. Asarum canadense and other species in the genus contain the nephrotoxic rodent carcinogen aristolochic acid, which is the FDA warns against consuming.^[1]^[2] ^[3] The birthwort family also contains the genus Aristolochia, known for carcinogens.

Wild ginger favors moist, shaded sites with humus-rich soil. The deciduous, heart-shaped leaves are opposite, and borne from the rhizome which lies just under the soil surface. Two leaves emerge each year from the growing tip. The curious jug-shaped flowers, which give the plant an alternate name, little jug, are borne singly in Spring between the leaf bases.

Wild ginger can easily be grown in a shade garden, and makes an attractive groundcover.

European Wild Ginger (Asarum europaeum) - flower

Taxonomy

Traditionally the genus Asarum was considered as a single genus with about 85 species. However there has been a trend among botanists to segregate the genus into separate genera, based on considerations of chromosome number and floral morphology :

Asarum s.s. (about 17 species), distributed in Asia (mainly China), North America and Europe
Heterotropa ( about 50 species), distributed in Asia
Asiasarum (3 to 4 species), distributed in Asia
Geotaenium (3 to 4 species), distributed in Asia
Hexastylis ( 8 to 9 species), distributed in North America

Study of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA, combined with morphological data, have yielded a better-resolved phylogenetic hypothesis, confirming the existence of the above-named genera. ^[4]

Asarum s.s. : the North American species are monophyletic and are derived from within the paraphyletic Asian species group.
Geotaenium is a sister to Asarum s.s., showing its close relationship to Asarum s.s.
Asiasarum is a sister to the Hexastylis + Heterotropa clade, showing several synapomorphies with this clade
Hexastylis : this genus has been recognized solely on the study by H.L. Blomquist ^[5]. However the above-mentioned DNA study provided indications that Hexastylis is not monophyletic and that some species of Hexastylis are more closely related to Asiatic species of Heterotropa than they are to other species of Hexastylis.
Heterotropa : this is a complex monophyletic group, well nested within the Asiasarum + Hexastylis + Heterotropa clade