Biennials; glaucous, glabrous throughout. Stems branched distally, (4-)6-16(-20) dm. Basal leaves: petiole 0.5-1.3 (-1.5) cm, not ciliate; blade spatulate or oblanceolate to obovate, 1.3-4(-7) cm × (4-) 6-13(-18) mm, margins usually dentate to repand, rarely entire. Cauline leaves (erect, appressed to stem at least partly); sessile; blade linear to linear-lanceolate, (1.8-)1.3-4.5 (-6) cm × (1-)1.7-7(-8) mm, (base auriculate or sagittate), margins entire. Racemes dense, terminal not elongated in fruit, (flower buds narrowly oblong). Fruiting pedicels usually horizontal to divaricate, rarely divaricate-ascending, straight, slender, (6-)7-14(-18) mm, often not flattened at base. Flowers: sepals erect, usually linear to linear-oblong, rarely oblong, 4-6(-7) × (0.8-)1-1.5 mm; petals lavender to purple, spatulate to obovate or oblong, (6-)7-9.5(-12) × (1.2-)1.5-2(-3) mm, margins not crisped, claw differentiated from blade, [slender, 3-4.5(-5.5) mm, narrowest at base]; nectar glands confluent, subtending bases of stamens; filaments tetradynamous, median pairs (5-)5.5-7.5(-8.5) mm, lateral pair (4-)5-6.5(7.5) mm; anthers exserted, linear to linear-oblong, 2-3(-4) mm, not circinately coiled; gynophore 0.5-2.5(-6) mm. Fruits erect distally, slightly torulose, usually strongly incurved, (overtopping buds), rarely straight and divaricate-ascending, terete, (1.8-) 2.8-5(-6.3) cm × 0.7-1 mm; ovules 52-70 per ovary; style cylindrical, (0.5-)0.8-1.5(-2) mm. Seeds 1-1.3 (-1.5) × 0.5-0.6(-0.8) mm. 2n = 26.

Flowering Jun-Aug. Alkaline flats; 1500-2000 m; Utah.

Thelypodium rollinsii is restricted mostly to Beaver, Carbon, Juab, Millard, Piute, Sanpete, and Sevier counties.