| Bistorta | |
|---|---|
 | |
| Bistorta officinalis in Japan | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Caryophyllales |
| Family: | Polygonaceae |
| Subfamily: | Polygonoideae |
| Genus: | Bistorta (L.) Scop.[1] |
| Synonyms[1] | |
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Bistorta is agenus of flowering plants in the familyPolygonaceae. As of February 2019[update] about 40 species are accepted. It has been supported as a separateclade bymolecular 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]
Species ofBistorta areperennialherbaceous plants. Their roots are fibrous, formingrhizomes. They have erect, unbranchedstems. Their leaves are usually longer than wide, mostly basal, but with some arranged alternately on the stems. Theinflorescences 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 threestyles. The fruits are in the form ofachenes, that are brown or dark brown, unwinged, and three-angled. Themonoploid number of chromosomes,x, is 11 or 12.[3]
In 1753,Carl Linnaeus divided up his genusPolygonum into unranked groups, one of which wasBistorta. In 1754,Giovanni Antonio Scopoli elevatedBistorta to a genus.[4]
Bistorta is placed in the subfamilyPolygonoideae, tribe Persicarieae, along with the generaKoenigia andPersicaria. A 2015 molecular phylogenetic study suggested that the tribes in Polygonoideae were related as shown in the following cladogram.[5]
| Polygonoideae |
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Within the tribe Persicarieae,Bistorta is most closely related toKoenigia:[5]
| Persicarieae |
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As of March 2019[update],Plants of the World Online accepted the following 42 species.[1]
