Persicaria longiseta

(Bruijn) Kitagawa

Rep. Inst. Sci. Res. Manchoukuo 1: 322. 1937.

Common names: Bristly lady’s-thumb
Basionym: Polygonum longisetum Bruijn in F. A. W. Miquel, Pl. Jungh. 3: 307. 1854
Synonyms: Persicaria caespitosa var. longiseta (Bruijn) C. F. Reed Polygonum caespitosum var. longisetum (Bruijn) Steward
Treatment appears in FNA Volume 5. Treatment on page 592. Mentioned on page 583.

Plants annual, 3–8 dm; roots also often arising from proximal nodes; rhizomes and stolons absent. Stems decumbent to ascending, branched, without noticeable ribs, glabrous. Leaves: ocrea hyaline to brownish, cylindric, 5–12 mm, chartaceous, base sometimes inflated, margins truncate, ciliate with bristles 4–12 mm, surface glabrous or strigose, not glandular-punctate; petiole 0.1–0.3(–0.6) cm, glabrous, leaves sometimes sessile; blade without dark triangular or lunate blotch adaxially, ovate-lanceolate to linear-lanceolate, 2–8 × 1–3 cm, base tapering to cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or sparingly strigose along veins abaxially, glabrous or strigose along midvein and margins adaxially, not glandular-punctate. Inflorescences terminal, sometimes also axillary, erect, uninterrupted, 10–40(–80) × 3–7 mm; peduncle 10–50 mm, glabrous; ocreolae overlapping, margins ciliate with bristles (0.5–)1–4(–6) mm. Pedicels ascending, 1–2 mm. Flowers 1–5 per ocreate fascicle, homostylous; perianth pinkish green proximally, roseate distally, glabrous, not glandular-punctate, scarcely accrescent; tepals 5, connate ca. 1/3 their length, obovate, 2.2–2.8 mm, veins not prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 5, included; anthers yellow, elliptic to ovate; styles 3, connate proximally. Achenes included, dark brown to black, 3-gonous, 1.6–2.3 × 1.1–1.6 mm, shiny, smooth.

Phenology: Flowering May–Oct.
Habitat: Floodplain forests and woodlands, shorelines of ponds, moist roadsides, waste places
Elevation: 0-300 m


V5 1206-distribution-map.gif

Introduced; B.C., N.B., Ont., Ala., Conn., Del., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Vt., Va., W.Va., Wis., e Asia, introduced also in Europe.


Persicaria longiseta is morphologically similar to another Asian species, P. posumbu (Buchanan-Hamilton ex D. Don) H. Gross (= P. caespitosa). Its spread in the United States since its introduction near Philadelphia in 1910 was summarized by A. K. Paterson (2000).

Selected References


Lower Taxa

... more about "Persicaria longiseta"
Harold R. Hinds† +  and Craig C. Freeman +
(Bruijn) Kitagawa +
Polygonum longisetum +
Bristly lady’s-thumb +
B.C. +, N.B. +, Ont. +, Ala. +, Conn. +, Del. +, Fla. +, Ga. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Nebr. +, N.J. +, N.Y. +, N.C. +, Ohio +, Pa. +, S.C. +, Tenn. +, Tex. +, Vt. +, Va. +, W.Va. +, Wis. +, e Asia +  and introduced also in Europe. +
0-300 m +
Floodplain forests and woodlands, shorelines of ponds, moist roadsides, waste places +
Flowering May–Oct. +
Rep. Inst. Sci. Res. Manchoukuo +
Introduced +
Persicaria caespitosa var. longiseta +  and Polygonum caespitosum var. longisetum +
Persicaria longiseta +
Persicaria sect. Persicaria +
species +