Biennials or perennials; (short-lived); distinctly glaucous throughout, glabrous. Stems usually branched distally, 1-4.4(-6) dm. Basal leaves (and proximal cauline): petiole 1-4 (-6) cm; blade (fleshy), usually ovate or obovate, rarely orbicular or spatulate, (2.2-) 4-10.5(-14) cm × (10-)15-43(-55) mm, margins usually lyrate, sinuate and repand, or dentate, rarely entire. Cauline leaves shortly petiolate; blade lanceolate or elliptic, much smaller than basal, margins entire or repand. Racemes somewhat lax, slightly elongated in fruit. Fruiting pedicels divaricate to divaricate-ascending, straight or incurved, slender, 4-12(-15) mm, slightly flattened at base. Flowers: sepals spreading to reflexed, oblong, (2.5-)3-4 × (0.8-)1-1.5(-1.8) mm; petals purple or lavender, usually oblanceolate, rarely spatulate, (2.5-)3-4.5 × 0.5-1 mm, margins not crisped, claw differentiated from blade; nectar glands confluent; filaments subequal, 2.5-3.8 mm; anthers oblong, 1-1.8 mm; gynophore 0.5-0.8(-1) mm. Fruits usually erect to ascending, rarely divaricate, torulose, straight or, sometimes, incurved, flattened, (2-)4-7.4 cm × 1-1.5 (-1.8) mm, (replum not constricted between seeds); ovules 32-44 per ovary; style subclavate, 0.5-1.2(-1.5) mm. Seeds (0.7-)1-1.5 × 0.5-0.8 mm.

Flowering Jun. Decomposing shale banks; ca. 1700 m; Idaho.

Thelypodium repandum is known from the shale banks of the Salmon River and its tributaries in Custer County.