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American bistort, smokeweed, western bistort


Habit Plants (10–)20–70(–75) cm; rhizomes contorted. Herbs, perennial; roots fibrous, rhizomatous.


erect, simple, glabrous.


ocrea brown, cylindric, 9–25(–32) mm, margins oblique, glabrous;

petiole attached to sheath 10–35(–50) mm, usually wingless, rarely winged distally, (10–)30–70(–110) mm;

blade elliptic to oblong-lanceolate or oblong-oblanceolate, (3.5–)5–22 × 0.8–4.8 cm, base tapered to rounded, rarely abruptly truncate or cuneate, often asymmetric, margins entire, sometimes wavy, apex usually acute to acuminate, rarely obtuse, abaxial face glabrous or pubescent with whitish or brownish hairs, glaucous, adaxial face glabrous, not glaucous;

cauline leaves 2–6, petiolate proximally, sessile distally, gradually reduced distally, blade elliptic or lanceolate to linear-lanceolate.

mostly basal, some cauline, alternate, petiolate or sessile;

ocrea persistent or disintegrating with age and deciduous entirely or distally, chartaceous;

blade linear or lanceolate to elliptic, oblong-ovate, or ovate, margins entire or obscurely and irregularly repand.


1(–2), short-cylindric to ovoid, (10–)20–40(–50) × (8–)12–25 mm, bulblets absent;

peduncle 1–10 cm.

terminal, spikelike.


ascending or spreading, 2–8(–11) mm.



1–2 per ocreate fascicle;

perianth white or pale pink;

tepals oblong, 4–5 mm, apex obtuse to acute;

stamens exserted;

anthers yellow, elliptic.

bisexual, 1–2 per ocreate fascicle, base not stipelike;

perianth nonaccrescent, white, greenish white, pink, or purplish pink, rarely red, campanulate, glabrous;

tepals 5, connate proximally ca. 1/5 their length, petaloid, monomorphic or slightly dimorphic, outer larger than inner;

stamens 5–8, sometimes poorly developed;

filaments distinct or connate basally, outer ones sometimes adnate to perianth tube, glabrous;

anthers yellow, pink, red, purple, or blackish, ovate to elliptic;

styles 3, erect or spreading, distinct or connate proximally;

stigmas 2–3, capitate.


yellowish brown or olive-brown, 3.2–4.2 × 1.3–2 mm, shiny, smooth.

included or exserted, brown to dark brown, unwinged, 3-gonous, glabrous.


embryo curved.


= 11, 12.


= 24.

Bistorta bistortoides


Phenology Flowering Jul–Sep.
Habitat Streambanks, moist or swampy meadows, alpine slopes
Elevation 1300-3800 m (4300-12500 ft)
from FNA
[WildflowerSearch map]
[BONAP county map]
Arctic and temperate North America; Europe; Asia
[BONAP county map]

Infrequent specimens of Bistorta bistortoides have basal leaf blades that are lance-ovate and abruptly contracted at the bases, and petioles distinctly winged distally, similar to those of B. officinalis.

Roots of western bistort were used in soups and stews by the Blackfoot, boiled with meat by the Cherokee, and used in a poultice that was applied to sores and boils by the Miwok (D. E. Moerman 1998).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species ca. 50 (4 in the flora).

Bistorta often is included in Polygonum in the broad sense or in Persicaria. It is accepted here as a distinct genus based on habit, morphology, and anatomy (K. Haraldson 1978; L.-P. Ronse Decraene and J. R. Akeroyd 1988). In the species of the flora area, the base of the petiole forms a long, tubular sheath distal to the node from which the leaf arises and proximal to the point of divergence of the petiole. Distal to the sheath is the ocrea, which usually is darker and thinner.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

1. Inflorescences narrowly elongate-cylindric, (15-)20-90 × 4-10 mm, usually bearing pyriform, pink to brown or purple bulblets proximally
B. vivipara
1. Inflorescences short-cylindric to ovoid, 10-70 × 8-25 mm, bulblets absent
→ 2
2. Leaf blade bases abruptly contracted, truncate to cuneate; petioles prominently winged distally; perianths pink
B. officinalis
2. Leaf blade bases usually tapered to rounded, rarely abruptly truncate or cuneate; petioles wingless or rarely winged distally; perianths white to pale pink, bright pink, or purplish pink
→ 3
3. Perianths bright pink or purplish pink; basal leaf blades with apices rounded to acute; plants (8-)10-40(-50) cm; n Canada, Alaska
B. plumosa
3. Perianths white or pale pink; basal leaf blades with apices usually acute to acuminate, rarely obtuse; plants (10-)20-70(-75) cm; sw Canada, w United States
B. bistortoides
Source FNA vol. 5, p. 596. FNA vol. 5, p. 594.
Parent taxa Polygonaceae > subfam. Polygonoideae > Bistorta Polygonaceae > subfam. Polygonoideae
Sibling taxa
B. officinalis, B. plumosa, B. vivipara
Subordinate taxa
B. bistortoides, B. officinalis, B. plumosa, B. vivipara
Synonyms Polygonum bistortoides, B. bistortoides var. oblongifolia, Persicaria bistortoides, Polygonum bistortoides var. linearifolium, Polygonum bistortoides var. oblongifolium Polygonum unranked B.
Name authority (Pursh) Small: Bull. Torrey Bot. Club 33: 57. (1906) (Linnaeus) Scopoli: Meth. Pl., 24. (1754)
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