Bistorta is a genus of flowering plants in the family Polygonaceae. As of February 2019[update] about 40 species are accepted. It has been supported as a separate clade by molecular phylogenetic analysis.[2]Bistorta species are native throughout much of the Northern Hemisphere, as far south as Mexico in North America and Thailand in Asia.[1]
Description
Species of Bistorta are perennialherbaceous plants. Their roots are fibrous, forming rhizomes. They have erect, unbranched stems. Their leaves are usually longer than wide, mostly basal, but with some arranged alternately on the stems. The inflorescences are spikelike. The individual flowers have five white to purple-pink (rarely red) tepals. The flowers are bisexual, although the 5–8 stamens are sometimes poorly developed. There are three styles. The fruits are in the form of achenes, that are brown or dark brown, unwinged, and three-angled. The monoploid number of chromosomes, x, is 11 or 12.[3]
Bistorta is placed in the subfamily Polygonoideae, tribe Persicarieae, along with the genera Koenigia and Persicaria. A 2015 molecular phylogenetic study suggested that the tribes in Polygonoideae were related as shown in the following cladogram.[5]
^ abcd"Bistorta (L.) Scop". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-03-01.
^Sanchez, A.; Schuster, T.M. & Kron, K.A. (2009). "A large-scale phylogeny of Polygonaceae based on molecular data". International Journal of Plant Sciences. 170 (8): 1044–1055. doi:10.1086/605121. S2CID84694521.
^Freeman, Craig C. & Hinds, Harold R. "Bistorta". In Flora of North America Editorial Committee (ed.). Flora of North America (online). eFloras.org. Retrieved 2019-03-14.
^ abSchuster, Tanja M.; Reveal, James L.; Bayly, Michael J. & Kron, Kathleen A. (2015). "An updated molecular phylogeny of Polygonoideae (Polygonaceae): Relationships of Oxygonum, Pteroxygonum, and Rumex, and a new circumscription of Koenigia". Taxon. 64 (6): 1188–1208. doi:10.12705/646.5.
