Hymenophysa pubescens C. A. Meyer in C. F. Ledebour, Icon. Pl. 2: 20. 1830, not Lepidium pubescens Desvaux 1814; Cardaria pubescens (C. A. Meyer) Jarmolenko; C. pubescens var. elongata Rollins

Perennials; (rhizomatous); often densely hirsute. Stems simple or several from base, erect or ascending, branched distally, (1-)1.5-3.5(-5) dm. Basal leaves (often withered by anthesis); not rosulate; petiole 0.5-1.5 cm; blade obovate to oblanceolate, (1-)2-6(-7) cm × 3-20 mm, margins dentate to sinuate. Cauline leaves sessile; blade oblong or lanceolate, 1-5(-8) cm × (3-)5-15(-30) mm, base sagittate, margins dentate or subentire, (surfaces pubescent). Racemes (usually corymbose, rarely paniculate), rarely elongated in fruit; rachis pubescent, trichomes often curved. Fruiting pedicels divaricate to ascending, straight or slightly curved, (terete), 3-9(-12) × 0.2-0.3 mm, pubescent. Flowers: sepals oblong, 1.4-2 × 0.7-1 mm; petals white, broadly obovate, (2.2-) 2.8-4 × 1-3 mm, claw 1-1.4 mm; stamens 6; filaments 2-2.5 mm, (glabrous); anthers 0.4-0.5 mm. Fruits (indehiscent), globose or, rarely, subglobose, (2-)3-4.4(-5) mm diam., (inflated), apically not winged, apical notch absent; valves thin, smooth, not veined, densely puberulent; style 0.5-1.5 mm. Seeds (brown or dark brown), ovoid, 1.5-2 × 1-1.5 mm. 2n = 16.

Flowering May-Sep. Roadsides, sagebrush communities, alkaline meadows, waste grounds, ditch and stream sides, fields, pastures; 400-2400 m; introduced; Alta., B.C., Man., Sask.; Calif., Colo., Idaho, Mich., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Oreg., Pa., Utah, Wash., Wis., Wyo.; c Asia; introduced also in South America, other parts of Asia.

Lepidium appelianum has become a noxious weed in most of its range in North America.