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-rayed 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.

Phenology: Flowering Jun–Jul.
Habitat: Rock crevices along streamlets near timberline
Elevation: ca. 3500 m

Colo.

Discussion

Of conservation concern.

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).

Selected References

None.

Lower Taxa