Mrs. Austin's knotweed

Polygonum douglasii Greene subsp. austiniae (Greene) E. Murray

Herbs. Stems ascending to erect, green to purplish, much-branched from base, not wiry, 5-10(-20) cm, papillose-scabridulous. Leaves uniformly distributed, articulated to ocreae, basal leaves persistent, distal leaves abruptly reduced to bracts, articulated to ocreae; ocrea 3-5 mm, papillose-scabridulous or glabrous, proximal part funnelform, distal part lacerate; petiole 0.1-2 mm; blade 1-veined, not pleated, ovate to elliptic or obovate, 5-15 × 4-7 mm, margins flat or narrowly revolute, papillose-denticulate, apex acute or mucronate. Inflorescences axillary and terminal, spikelike, slender; cymes spaced along branches, 1-4-flowered. Pedicels exserted from ocreae, reflexed, 1-2.5 mm. Flowers closed; perianth (1.8-)2-2.6 mm; tube 20-28% of perianth length; tepals overlapping, green or purple, with narrow whitish margins, petaloid or sepaloid, oblong, cucullate, navicular, apex rounded; midveins unbranched; stamens 8. Achenes enclosed in perianth, black, elliptic to obo-vate, 2-2.5 mm, faces subequal, shiny, ± smooth.

Flowering Jun-Sep. Dry to moist flats on banks, sagebrush plains, and ponderosa pine forests; 1300-1600 m; Alta., B.C.; Calif., Idaho, Mont., Nev., Oreg., Wash., Wyo.