Biennials or perennials; (short-lived, caudex often woody). Trichomes of leaves 2-rayed, mixed with 3-rayed ones. Stems erect, unbranched, (1.4-)2.5-8(-10) dm. Basal leaves: blade filiform to narrowly linear, 5-17 cm × 0.4-3 mm, (somewhat revolute, appearing terete), base attenuate, margins denticulate, apex subacuminate. Cauline leaves sessile; blade margins entire or remotely denticulate. Racemes considerably elongated in fruit. Fruiting pedicels divaricate to ascending, slender, narrower than fruit, 5-14 mm. Flowers: sepals oblong to linear-oblong, 7-11 mm, lateral pair saccate basally; petals orange-yellow to yellow, broadly obovate to suborbicular, 15-20(-25) × 5-10 mm, claw 6-13 mm, apex rounded; median filaments 7-14 mm; anthers linear, 2.3-3.5 mm. Fruits widely spreading to ascending, narrowly linear, curved or slightly twisted, somewhat torulose, (4-) 7-12(-15) cm × 1.2-2.2(-2.5) mm, slightly latiseptate, not striped; valves with prominent midvein, pubescent outside, trichomes 2 and 3 (or 4)-rayed, glabrous inside; ovules 40-72 per ovary; style cylindrical, slender, 0.5-2 (-2.5) mm, sparsely pubescent; stigma subentire to slightly 2-lobed, lobes as long as wide. Seeds ovoid, 1.5-2.3(-2.7) × 0.9-1.5 mm; wing appendage-like, distal. 2n = 36. Flowering Feb-May. Sandy areas bordering sage scrub or chaparral, sand deposits derived from sandstone; of conservation concern; 100-400 m; Calif. Erysimum teretifolium is a highly endangered species known only from Santa Cruz County.