American Bistort (Bistorta bistortoides)

Bistorta bistortoides
Conservation status
Secure  (NatureServe)[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Polygonaceae
Genus:	Bistorta
Species:	B. bistortoides
Binomial name
Bistorta bistortoides (Pursh) Small
Synonyms[2]
Persicaria bistortoides (Pursh) H.R.Hinds Polygonum bistortoides Pursh

Bistorta bistortoides, commonly called western bistort, is a perennial herb in the buckwheat family.

Western bistort is a herbaceous plant, one with no woody parts, that is 10 to 75 centimeters (4 to 30 in) tall when full grown, though more typically between 20 and 70 cm (8 and 28 in). Each plant has one to three flowering stems.^[3] It grows perennially from a twisted rhizome at a shallow depth in the soil.^[4] They range from pea sized up to approximately thumb sized.^[5]

The ocreae, the sheath formed from two stipules at the base of each leaf, is round, hairless, brown, smooth, and 9–32 mm long.^[6] Plants have mostly basal leaves, those attached to the plant at ground level, but also have some smaller leaves on the flowering stems.^[4] Leaves are long and narrow, usually 5–22 centimeters long, only rarely as short as 3.5 cm, and 0.8 to 4.8 cm wide. Their shape is lanceolate, oblanceolate, or elliptic with an often asymmetrical base. There are two to six leaves attached to each flowering stem with the lower ones being attached by short stalks and the upper ones without.^[6]

The dense cylindrical to oblong inflorescence is 1–5 cm (0.5–2 in) long, though most often 2–4 cm, and about 0.8–2.5 cm in diameter. Usually just one per stem, but occasionally two.^[6] They are packed with small white to pinkish flowers, each a few millimeters wide and with protruding stamens.^[3] Each individual flower has five tepals, petal like sepals, and produces a sharp smell somewhat like that of dirty socks.^[7] The blooming period is in the local elevation's springtime.^[8] This is as early as May at low elevations and as late as September at high altitudes.^[7][3]

The seed-like fruit is simple and dry, an achene, with a shiny yellow-brown to olive-brown surface and three sides.^[3][9] They measure 3.2–4.2 mm long by 1.3–2 mm wide.^[3]

Bistorta bistortoides was scientifically described and named Polygonum bistortoides by Frederick Traugott Pursh in 1813.^[2] He was working with specimens collected by Meriwether Lewis on 12 June 1806.^[10] The botanist John Kunkel Small moved it to the genus Bistorta in 1906, creating its accepted name. Together with its genus it is classified in the family Polygonaceae. It has no accepted varieties, but according to Plants of the World Online it has 27 synonyms.^[2]

The species name, bistortoides, was applied by Pursh for its similarity to the Eurasian Bistorta officinalis.^[11] Bistorta bistortoides is very often known by the common name western bistort;^[12] it is similarly known as American bistort.^[3] Other names include mountain buckwheat,^[13] mountain meadow buckwheat,^[14] and mountain meadow knotweed.^[4] Somewhat non-specifically it is known as just smartweed, knotweed, and bistort,^[15] Lastly, it is sometimes called smokeweed,^[3] ladies' thumb,^[16] or snakeweed,^[15] but plants in the genus Gutierrezia are frequently known as snakeweeds.^[17]

In the Cheyenne language they are called ā ĭs' tō mĭmĭs' sĭs and the diminutive name toco.^[5]

Western bistort is distributed throughout the mountainous west of North America from British Columbia and Alberta south to California and eastwards into the Rocky Mountains with some plants found in the north of Mexico in Chihuahua.^[18] They are typically found at high elevations of 1,300 to 3,800 meters (4,300 to 12,500 ft),^[3] however the Jepson Herbarium reports that it is also uncommonly found in coastal freshwater marshes at sealevel to 20 m (66 ft) in northern and central California.^[19]

The plant grows from foothills to above the timberline.

Rodents and bears consume the roots, and elk and deer browse the foliage.^[4]

Western bistort is an important food plant in traditional hunting and gathering practices of many peoples living in the Mountain West, including the Blackfoot and Cheyenne.^[4] The roots are edible either raw, fire-roasted, or boiled;^[20] they are starchy and lacking a bitter flavor when raw, but older rootstocks are moderately fibrous. The taste is somewhat like that of water chestnut (Eleocharis dulcis) when cooked. It has larger rootstalks than the related alpine bistort (Bistorta vivipara).^[21]

The young leaves are eaten raw or cooked and have a tart, though pleasant, flavor.^[20] The seeds are edible either as a boiled whole grain or ground into flour and used to make bread.^[22] The writer Doug Benoliel cautions foragers against eating a large amounts of this plant until digestion becomes accustomed to it;^[4] raw parts of all knotweeds can cause diarrhea if consumed to excess.^[23]

In traditional Cheyenne cooking practices the roots were boiled with meat and were held in high regard.^[5]

It is occasionally cultivated in naturalistic meadows. It is hardy in USDA zones 3b to 8b, but requires moist to wet soils.^[24]

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