Persicaria capitata

(Buchanan-Hamilton ex D. Don) H. Gross

Bot. Jahrb. Syst. 49: 277. 1913.

Common names: Pink-head knotweed
Basionym: Polygonum capitatum Buchanan-Hamilton ex D. Don Prodr. Fl. Nepal., 73. 1825
Treatment appears in FNA Volume 5. Treatment on page 579. Mentioned on page 580.

Plants annual or perennial, 0.5–5 dm; roots also often arising from proximal nodes. Stems prostrate, glabrous or glandular-pubescent. Leaves: ocrea brown or reddish brown, cylindric to funnelform, 5–12 mm, chartaceous, base inflated or not, margins oblique, eciliate or ciliate with bristles to 1.5 mm, surface lanate, sometimes also glandular-pubescent; petiole 2–5 mm, winged distally; blade ovate to elliptic, 1.5–4(–6) × 0.6–2.5(–3.3) cm, base cuneate or tapering, margins ciliate with reddish, multicellular hairs, apex acute, faces glandular-pubescent abaxially and adaxially, not glandular-punctate. Inflorescences terminal, 5–20 × 7-18 mm; peduncle 10–40 mm, glabrous or stipitate-glandular in distal 1/5; ocreolae overlapping, margins eciliate. Pedicels spreading, 0.5–1 mm. Flowers 1–5 per ocreate fascicle; perianth greenish white proximally, pinkish distally, urceolate, glabrous, nonaccrescent; tepals 5, elliptic, 2–3 mm, apex acute to obtuse; stamens 8, filaments distinct, free; anthers pink to red, elliptic; styles 3, connate to middle or distally. Achenes included, reddish brown to brownish black, 3-gonous, 1.5–2.2 × 1–1.5 mm, shiny, smooth or minutely punctate.

Phenology: Flowering Jun–Sep.
Habitat: Disturbed, urban places
Elevation: 0-500 m


V5 1187-distribution-map.gif

Introduced; Calif., La., Oreg., Asia (Bhutan, w China, n India, Nepal), introduced also in the Pacific Islands (Hawaii).


Persicaria capitata is planted as a garden groundcover. It escapes infrequently in the flora area; once established outside of cultivation it can be difficult to eradicate.

Selected References


Lower Taxa

... more about "Persicaria capitata"
Harold R. Hinds† +  and Craig C. Freeman +
(Buchanan-Hamilton ex D. Don) H. Gross +
Polygonum capitatum +
Pink-head knotweed +
Calif. +, La. +, Oreg. +, Asia (Bhutan +, w China +, n India +, Nepal) +  and introduced also in the Pacific Islands (Hawaii). +
0-500 m +
Disturbed, urban places +
Flowering Jun–Sep. +
Bot. Jahrb. Syst. +
Introduced +
Persicaria capitata +
Persicaria sect. Cephalophilon +
species +