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Knorringia
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Polygonaceae
Subfamily:	Polygonoideae
Genus:	Knorringia; (Czukav.) Tzvelev

Knorringia is a genus of plants in the family Polygonaceae. It is native to Central Asia and Siberia.^[1]

Description

Species of Knorringia are perennial herbaceous plants growing to about 40 cm (16 in) tall from a slender, often branched rhizome. The stem may be more-or-less upright or decumbent. The leaves are arranged alternately, usually lobed, carried on a short five-sided leaf stalk (petiole) with two distinct wings. The ochreas are 3–20 mm (0.1–0.8 in) long, and form membranous tubes that partly or fully wrap around the stem. The inflorescence is either a panicle made up of a few racemes or a single raceme. The flowers usually have five greenish-white tepals and eight stamens, included within the flower. They are either bisexual or have the gynoecium poorly developed. The fruits are in the form of achenes. The seeds have a thick outer layer (exotesta) and a very thin inner layer (endotesta).^[2]

Taxonomy

In 1966, Anna Czukavina created a section within the genus Polygonum, P. sect. Knorringia. The section was raised to the rank of genus in 1987 by Nikolai Tzvelev,^[3] and independently in 1989 by Suk-Pyo Hong.^[2] The genus is placed in the tribe Polygoneae in the subfamily Polygonoideae. A 2015 molecular phylogenetic study suggested that it was sister to all the remaining genera in the tribe, although only K. sibirica was included in the analysis.^[4]

Polygoneae

Knorringia

Polygonum ciliinode (syn. Fallopia ciliinodis)

DAP clade

Duma

	Atraphaxis

	Polygonum

RMF clade

Reynoutria

	Muehlenbeckia

	Fallopia s.s.

Species

As of March 2019^[update], Plants of the World Online accepted the following species:^[1]

Knorringia pamirica (Korsh.) Tzvelev
Knorringia sibirica (Laxm.) Tzvelev

References

^ ^a ^b ^c "Knorringia (Czukav) Tzvelev", Plants of the World Online, Royal Botanic Gardens, Kew, retrieved 2019-03-09
^ ^a ^b Hong, Suk-Pyo (1989), "Knorringia (= Aconogonon sect. Knorringia), a new genus in the Polygonaceae", Nordic Journal of Botany, 9 (4): 343–357, doi:10.1111/j.1756-1051.1989.tb01009.x
^ "Plant Name Details for Knorringia (Czukav.) Tzvelev", The International Plant Names Index, retrieved 2019-03-09
^ Schuster, 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