Biennials; moderately to densely pilose. Stems erect or ascending, unbranched or branched distally, 2-12 dm. Basal leaves rosulate; petiole 1-8 cm; blade oblanceolate or oblong (in outline), 2-24 cm × 5-90 mm, margins usually pinnatifid to pinnatisect, rarely dentate-sinuate (lobes dentate). Cauline leaves (distalmost) shortly petiolate; blade linear to narrowly oblanceolate, margins entire or dentate. Racemes (densely flowered), without a terminal cluster of sterile flowers, (sometimes proximalmost flowers bracteate). Fruiting pedicels ascending, 4-18 mm, glabrous or pilose. Flowers: sepals erect, (dark purple in bud becoming paler or greenish), narrowly ovate to lanceolate, 4.5-9.5 × 1.5-2 mm, (equal); petals purple, 7-12 mm, blade 3-4 × 1-1.5 mm, crisped, claw oblanceolate to spatulate, 4-9 × 1-2 mm; filaments tetradynamous, median pairs 4.5-10 mm, lateral pair 3-8.5 mm; anthers narrowly oblong, equal, 2-3.5 mm. Fruits ascending to divaricate, terete, 2-18 cm × 1-1.5 mm; valves each with obscure midvein; ovules 152-198 per ovary; style obsolete or, rarely, to 1 mm; stigma slightly 2-lobed. Seeds 1-2 × 0.7-1 mm.

Flowering late Mar-early Jul. Flats, rocky slopes, scrub and sagebrush communities, pinyon-juniper woodland; 600-2800 m; Calif., Idaho, Nev., Oreg., Utah.

Caulanthus pilosus is found in northeastern California, southwestern Idaho, Nevada, eastern and southern Oregon, and western Utah.