Draba stenopetala

Perennials; (pulvinate); caudex branched (covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. Stems unbranched, (0.02-)0.07-0.2 (-0.3) dm, pubescent through-out, trichomes simple and short-stalked, 2-5-rayed, 0.1-0.5 mm, (sometimes simple ones very sparse). Basal leaves (densely imbricate); rosulate; petiolate; petiole base and margin ciliate, (trichomes simple and 2-rayed, 0.2-0.5 mm); blade obovate to oblong-spatulate, 0.2-0.6 (-0.8) cm × 1-2(-3) mm, margins entire, surfaces often pubescent with simple and stalked, 2-5-rayed trichomes, 0.2-0.9 mm, sometimes glabrous and trichomes on margins only. Cauline leaves 0. Racemes 2-5-flowered, ebracteate, not or slightly elongated in fruit; rachis slightly flexuous, pubescent as stem. Fruiting pedicels divaricate, straight, 2-5(-7) mm, pubescent as stem. Flowers: sepals (spreading or reflexed), oblong, 2-3.5 mm, pubescent, (trichomes simple and 2-rayed); petals yellow or purple, linear, 2.5-5 × 0.3-0.7 mm; anthers ovate, 0.3-0.4 mm. Fruits suborbicular, plane, inflated basally, flattened distally, 3-5 × 3-4 mm; valves glabrous or puberulent, trichomes simple, 0.02-0.3 mm; ovules 4-10 per ovary; style 0.2-0.6 mm. Seeds ovoid, 1-1.3 × 0.8-1 mm. 2n = 24, 64.

Flowering May-Jul. Rock outcrops, talus, rocky ridges, alpine tundra; 100-1900 m; Yukon; Alaska; e Asia (Russian Far East).

Different chromosome counts for Draba stenopetala were reported as 2n = 24 from North America and 2n = 64 from the Russian Far East (S. I. Warwick and I. A. Al-Shehbaz 2006). It is unlikely that a single species is involved, and further work is needed to verify the counts from North America.