Perennials; (cespitose, caudex woody, many-branched, with persistent petiolar remains); puberulent. Stems simple from base, erect, unbranched or branched (few) distally, (0.2-) 0.5-1(-1.4) dm. Basal leaves (often deciduous); not rosulate; blade spatulate to oblanceolate, 1-2.5(-3.2) cm × 2-6(-9) mm, margins entire or apically 3(-5)-toothed or -lobed. Cauline leaves sessile; blade usually oblanceolate or oblong, rarely obovate, (0.8-)1.3-2.5 cm × (2-)4-7 mm, base obtuse or cuneate, not auriculate, margins entire or apically 3(-5)-toothed. Racemes slightly elongated in fruit; rachis puberulent, trichomes straight or curved. Fruiting pedicels divaricate-ascending, straight, (slender or slightly stout, terete), (2.5-)3-4.2(-5) × 0.4-0.5 mm, usually puberulent throughout, rarely glabrate. Flowers: sepals suborbicular to oblong-ovate, 1.2-2 × 1-1.5 mm; petals white, obovate, 2-3.2(-4) × 1.5-2 mm, claw 0.5-1 mm; stamens 6; filaments 1.7-2.3 mm, (glabrous); anthers 0.4-0.7 mm. Fruits suborbicular to broadly ovate, (2.5-)3-4.3(-5) × (2-)2.3-4 mm, apically winged, apical notch 0.1-0.4 mm deep; valves thin, smooth, not veined, glabrous or sparsely puberulent; style 0.5-1 mm, exserted beyond apical notch. Seeds oblong-ovate, (1.8-)2-2.3 × 1-1.2 mm. 2n = 32.

Flowering May-Jun. Playas of sagebrush plains and mesa, vernal ponds; 800-1600 m; Idaho, Nev., Oreg.

Lepidium davisii is restricted to six counties in Idaho (Ada, Elmore, Owyhee, Twin Falls), Nevada (Elko), and Oregon (Malheur).