Thelypodium purpusii Brandegee, Zoë 5: 232. 1906 (as purpusi); Sisymbrium kearneyi Rollins; S. purpusii (Brandegee) O. E. Schulz; S. vernale (Wooton & Standley) O. E. Schulz; T. vernale Wooton & Standley

Annuals; (often glaucous), glabrous throughout. Stems unbranched or branched distally, 1.5-5(-7) dm. Basal leaves (soon withered); not rosulate; petiole 0.5-3 cm; blade oblanceolate, 1.5-9 cm × 5-30 mm, margins pinnatifid to dentate-sinuate. Cauline leaves (proximalmost) petiolate or (distal) sessile; blade (proximalmost) oblanceolate, (distal) ovate to oblong, base subamplexicaul or auriculate, margins (proximalmost) pinnatifid to dentate-sinuate, or (distal) entire. Racemes lax. Fruiting pedicels ascending to divaricate, straight, 3-7(-10) mm. Flowers: sepals erect, green or purplish, 3-4.5 × 0.7-1.2 mm; petals white, oblanceolate, 4-5.5 × 1-1.5 mm, claw 2-3 mm; median filament pairs 3-4 mm; anthers ovate, 0.5-0.8 mm; gynophore 0.2-0.4 mm. Fruits divaricate to ascending or spreading, straight or curved, torulose, 3-6.5 cm × 1-1.2 mm; ovules 46-114 per ovary; style subclavate, 0.7-1.5 mm; stigma entire or obscurely 2-lobed. Seeds 0.9-1.2 × 0.5-0.7 mm.

Flowering Feb-May. Juniper woodlands, rocky slopes, shale grounds, loose gypsum, barren areas, clay banks of rocky hillsides, shrub communities; 1400-2100 m; Ariz., N.Mex., Tex.; Mexico (Coahuila).