Polygonum majus

Herbs. Stems erect, green, simple or branched, ± wiry, 15–60 cm, usually papillose-scabridulous. Leaves uniformly distributed, articulated to ocreae, basal leaves often caducous, distal leaves abruptly reduced to bracts, articulated to ocreae; ocrea 5–12 mm, glabrous or papillose-scabridulous, proximal part cylindric, distal part lacerate or disintegrating into fibers; petiole 0.1–2 mm; blade 1-veined, not pleated, linear to narrowly oblong or lanceolate, 15–70 × 2–8 mm, margins revolute, papillose-denticulate, apex acute or mucronate. Inflorescences axillary and terminal, spikelike, elongate; cymes spaced along branches, 2–5-flowered. Pedicels exserted from ocreae, reflexed, 0.5–1 mm. Flowers open or semi-open; perianth (3.5–)4–5 mm; tube 9–17% of perianth length; tepals overlapping, uniformly white to pink, petaloid, oblong to oblong-obovate, cucullate, navicular in distal 1/4, apex rounded; midveins unbranched or with short lateral branches; stamens 8. Achenes enclosed in perianth, black, elliptic, 3.5–5 mm, faces subequal, shiny or dull, smooth or striate-tubercled.

Phenology: Flowering May–Aug.
Habitat: Dry plains, meadows, sometimes on serpentine
Elevation: 500-2000 m

B.C., Calif., Colo., Idaho, Nev., Oreg., Utah, Wash., Wyo.

Discussion

Selected References

None.

Lower Taxa