Biennial to perennial herb usually with lax rosette. Stems erect or ascending, glabrous, 1-2-(3) m tall, becoming woody below with prominent lf base scars. Lvs all glabrous and glaucous. Lower lvs petiolate, obovate or elliptic, 10-30 × 5-15 cm, not lobed or lyrate-pinnatifid with large terminal and 1-(2) pairs of small lateral lobes; margins sinuate, toothed. Upper lvs less divided, sessile, amplexicaul, elliptic-oblong or narrowly triangular, entire or toothed, 2-10 × 0.7-2 cm. Racemes to 60 cm long; open fls well below level of buds. Sepals narrow-oblong, (7)-8-11 × (1.5)-2-3 mm. Petals pale yellow or white, 15-25 × 5-8 mm. All stamens erect. Silique terete, glabrous, linear-lanceolate, slightly constricted between seeds, 50-60-(80) × 3-4 mm; gynophore 0; valves with prominent median and weaker lateral network of veins; beak conic, usually seedless, 5-10-(15) mm long. Seeds dark brown with greyish bloom, c. 2 mm diam.