Stems 2-11 dm, glabrous throughout. Cauline leaves: blade conduplicate distally, margins entire, surfaces glabrous. Racemes not secund; rachis flexuous. Fruiting pedicels 10-32 mm, glabrous. Flowers: sepals dark purple-black, 7-8 mm, glabrous; petals dark purple, 10-12 mm; adaxial filaments 8-10 mm. Fruits divaricate-ascending, straight; valves glabrous. 2n = 28.

Flowering May-Jul. Serpentine grasslands; of conservation concern; Calif.

Subspecies niger is known from the Tiburon Peninsula, Marin County.