Polygonum patulum

M. Bieberstein

Fl. Taur.-Caucas. 1: 304. 1808.

Treatment appears in FNA Volume 5. Treatment on page 560. Mentioned on page 547, 549, 552.

Plants green or bluish green, heterophyllous. Stems mostly ascending or erect, branched from base, not wiry, 20–80 cm. Leaves: ocrea 7–9 mm, proximal part cylindic, distal part disintegrating into straight fibers; petiole 0.2–1 mm; blade green or bluish green, linear to lanceolate, 25–40 × 4–8 mm, margins flat, apex acute; stem leaves 2–4 times as long as branch leaves; distal leaves abruptly reduced and not overtopping flowers (shorter than or equaling flowers). Inflorescences axillary and terminal, spikelike; cymes aggregated at tips of stems and branches, 1–3-flowered. Pedicels enclosed in ocreae, 1.5–2 mm. Flowers closed or semi-open; perianth 2.2–3 mm; tube 15–30% of perianth length; tepals overlapping, green with white to pink margins, petaloid, not keeled, oblong, cucullate; veins branched; stamens 8. Achenes slightly exserted from perianth, light brown to dark brown, ovate, 3-gonous, 2–2.3(–2.8) mm, faces subequal, concave, apex not beaked, edges concave, dull, striate-tubercled; late-season achenes uncommon, 2.5–4 mm.

Phenology: Flowering Jul–Oct.
Habitat: Waste places
Elevation: 0-800 m


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Introduced; Ala., Ill., Wash., Eurasia, n Africa.


The name Polygonum patulum has been misapplied to a distinctive form of P. ramosissimum in saline marshes in California (M. Costea and F. J. Tardif 2003b).

Selected References


Lower Taxa