Annuals; sparsely pilose (at least distally). Stems simple or several from base, erect to ascending, branched distally, 1-6(-7) dm. Basal leaves (withered by anthesis); not rosulate. Cauline leaves sessile; blade lanceolate to linear, 2-7.5(-10) cm × 2-10 mm, base cuneate to attenuate, not auriculate, margins entire or sparsely dentate subapically. Racemes considerably elongated in fruit, (lax); rachis usually pilose, rarely glabrous, trichomes usually curved, cylindrical. Fruiting pedicels divaricate to horizontal, straight or slightly sigmoid, (terete), 5-15 × 0.15-0.2 mm, pilose adaxially. Flowers: sepals oblong, 1.8-2.5 × 0.9-1.5 mm; petals lemon yellow (fading whitish), spatulate, 2.8-4 × 1.2-1.8 mm, claw 1-1.4 mm; stamens 6; filaments 1.8-2.5 mm, (glabrous); anthers 0.5-0.6 mm. Fruits broadly ovate, 3-3.8(-4) × 2.8-3.2(-3.5) mm, apically not winged, apical notch 0(-0.1) mm deep; valves thin, obscurely veined, smooth or minutely papillate, glabrous; style 0.3-0.8(-1) mm, exserted beyond apical notch. Seeds (reddish brown), oblong, 1.8-2.2 × 1-1.4 mm. 2n = 16.

Flowering Mar-Apr. Arroyos, washes, alkaline bottoms and meadows, dry hillsides; of conservation concern; 500-700 m; Calif.

Lepidium jaredii is known from Fresno, San Benito, and San Luis Obispo counties.