Draba weberi

Perennials; (cespitose); caudex branched (covered with persistent, somewhat thickened, petioles); not scapose. Stems unbranched, 0.2-0.6(-1) dm, glabrous or sparsely pubescent throughout, trichomes simple, sessile or subsessile, 2- or 3-rayed, 0.2-0.6 mm. Basal leaves rosulate; petiolate; petiole margin ciliate, (trichomes simple, 0.2-0.6 mm); blade linear-oblanceolate, 0.4-1.5 cm × 0.8-1.7 mm, margins entire, (pubescent as petiole), surfaces pubescent abaxially with (appressed), simple, subsessile or sessile, 2-4-rayed trichomes, 0.1-0.4 mm, glabrous or subapically sparsely pubescent adaxially with simple trichomes. Cauline leaves 1-3; sessile; blade linear-oblong, margins entire, surfaces pubescent as basal. Racemes 5-15-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. Fruiting pedicels divaricate-ascending, straight, 2-6 mm, glabrous or sparsely pubescent as stem. Flowers: sepals ovate, 1.5-2 mm, pubescent, (trichomes simple and 2-rayed); petals yellow, spatulate, 3-4 × 1.2-1.8 mm, (flared, clawed); anthers ovate, 0.3-0.4 mm. Fruits ovate, plane, flattened, 4-8 × 2-3 mm; valves glabrous; ovules 16-18 per ovary; style 0.2-0.3 mm. Seeds ovoid, 1-1.2 × 0.6-0.7 mm.

Flowering Jun-Jul. Rock crevices along streamlets near timberline; of conservation concern; ca. 3500 m; Colo.

Draba weberi is an apomictic species allied to D. exunguiculata, D. grayana, and D. streptobrachia. From those, it is distinguished by having ovate fruits, clawed petals, and sessile, 2-4-rayed trichomes with untwisted rays often appressed to leaf and stem surfaces. Draba weberi is known from near North Star Peak in central Colorado (Summit County).