Draba serpentina

Perennials; (cespitose); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. Stems unbranched, 0.3-1.3 dm, glabrous throughout. Basal leaves rosulate; sessile; blade obovate to obovate-oblanceolate, 0.4-1 cm × (2-)2.5-4(-5) mm, margins entire, (ciliate, trichomes simple, 0.2-0.5 mm, apex acute), surfaces glabrous. Cauline leaves 0. Racemes 6-14-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous. Fruiting pedicels divaricate-ascending, straight, 5-13 mm, glabrous. Flowers: sepals ovate, 2-3 mm, glabrous; petals white, spatulate to obovate, 5-6.5 × 2-3 mm; anthers ovate to oblong, 0.4-0.5 mm. Fruits lanceolate to narrowly oblong, slightly twisted or plane, flattened, 6-12 × 2-3.5 mm; valves glabrous; ovules 8-16 per ovary; style 0.6-1.8(-2.5) mm. Seeds oblong, 1.1-1.4 × 0.7-0.8 mm. 2n = 52.

Flowering May-Jul. Rock outcrops, talus, and gravelly soil in mixed conifer and subalpine meadow communities; of conservation concern; 3200-3600 m; Nev.

Draba serpentina has been treated by other authors as a variety or synonym of D. oreibata. As indicated by I. A. Al-Shehbaz and M. D. Windham (2007), the two taxa are morphologically distinct, have different chromosome numbers, and are separated by over 480 kilometers. They are treated herein as separate species. Draba serpentina is known only from the Snake Range (White Pine County) and the Toiyabe Mountains (Lander County) in central Nevada.