31. Lepidium papilliferum (L. F. Henderson) A. Nelson & J. F. Macbride, Bot. Gaz. 56: 474. 1913.
Lepidium montanum Nuttall var. papilliferum L. F. Henderson, Bull. Torrey Bot. Club 27: 342. 1900; L. montanum subsp. papilliferum (L. F. Henderson) C. L. Hitchcock
Annuals or biennials; puberulent, (trichomes clavate). Stems several from base, ascending, branched (several) distally, (0.3-)0.5-2.3(-4) dm. Basal leaves (soon deciduous), not rosulate; blade often bipinnately divided. Cauline leaves attenuate to petiolelike base, to 1 cm; blade pinnatifid to pinnatisect, obovate to oblanceolate in outline (lobes oblong to linear), 0.5-4 cm × 3-15 mm (smaller distally), base not auriculate, margins (of lobes) entire or dentate. Racemes slightly elongated, (dense) in fruit; rachis puberulent, trichomes straight or curved, clavate. Fruiting pedicels divaricate to horizontal, straight or recurved, (not winged), (2.5-)3-6(-7.5) × 0.2-0.3 mm, puberulent adaxially or throughout. Flowers: sepals ovate to broadly oblong, 1.5-2.2 × 0.8-1.1 mm; petals white, orbicular to spatulate, 2.5-3.7(-4) × 1.5-2.5 mm, claw 0.8-1.5 mm; stamens 6; filaments 1.5-2 mm, (trichomes clavate); anthers 0.4-0.6 mm. Fruits orbicular to broadly ovate, 2.2-3.6 × 2-3.4 mm, apically winged, apical notch 0.1-0.3 mm deep; valves thin, smooth, often not veined, glabrous; style 0.2-0.8 mm, exserted beyond apical notch. Seeds ovate, 1.2-1.8 × 0.9-1.1 mm.
Flowering May-Jun. Sagebrush plains, desert flats, edge of playa; of conservation concern; 600-1700 m; Idaho.
Lepidium papilliferum is distributed in Ada, Canyon, Elmore, Gem, Owyhee, and Payette counties.