Annual herb with laxly caespitose rosette. Stems erect, hairy below, to 1 m tall. Rosette and lower stem lvs pinnate to lyrate pinnatifid, rarely simple in weak plants or seedlings, hairy or bristly especially on midrib beneath, (5)-10-15-(30) × (1)-3-5-(9) cm; margins toothed; terminal lobe small, usually ternate; lateral lobes in (4)-5-8 pairs, subacute. Upper stem lvs sessile, becoming simple, toothed to entire, lanceolate to linear, bristly especially on margins, 10-20 × 2-6 mm. Racemes to 40 cm long; open fls overtopping or about level with buds. Sepals oblong, 2-3 × 0.5-1 mm. Petals pale yellow, becoming whitish, veined with yellow or sometimes violet, 4-5-(7) × 1-1.5-(2) mm. All stamens erect. Silique terete, glabrous, linear, constricted between seeds, (30)-40-50-(70) × 1.5-2.5 mm; gynophore 0; valves with prominent median vein; beak linear, usually 1-seeded, 8-14-(20) mm long, (⅓)-1/2× length of valves. Seeds dark brown, 1-1.5 mm diam.