Draba oblongata

Perennials; (cespitose); caudex branched (with persistent leaf remains); sometimes scapose. Stems unbranched, (0.2–)0.4–1.5(–1.9) dm, pubescent throughout, trichomes simple, 0.4–0.8 mm, and short-stalked, 4–10-rayed, 0.05–0.3 mm, (mostly branched distally). Basal leaves rosulate; petiolate; petiole base and margin ciliate, (trichomes simple, 0.3–1 mm); blade oblanceolate to lanceolate, 0.4–1.5 cm × 1.5–5 mm, margins entire, surfaces pubescent with simple and stalked, 2- or 3-rayed trichomes, 0.4–1 mm, with short-stalked, 8–12-rayed, stellate ones, 0.1–0.2 mm. Cauline leaves 0–2; sessile; blade oblong to broadly ovate, margins entire, surfaces pubescent as basal. Racemes 5–13(–18)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem distally. Fruiting pedicels divaricate to ascending, straight, 2–6(–8) mm, pubescent as rachis. Flowers: sepals ovate, 2–3 mm, pubescent, (trichomes simple and short-stalked, mostly 2-rayed); petals white, spatulate to obovate, 3.5–5 × 1.5–2.5 mm; anthers ovate, 0.2–0.3 mm. Fruits elliptic to oblong, plane, slightly flattened, 4–8(–9.5) × 2–3(–4) mm; valves pubescent, trichomes short-stalked, (2–)5–12-rayed, 0.05–3 mm; ovules 24–36 per ovary; style 0.2–0.8 mm (stigma considerably wider than style, often appearing 2-lobed). Seeds ovate, 0.7–1 × 0.5–0.6 mm. 2n = 64.

Phenology: Flowering Jun–Jul.
Habitat: Ridges and hillsides, sand and gravel flood plains, swales, tundra
Elevation: 0-400 m

Greenland, N.W.T., Nunavut, Alaska, e Asia (Russian Far East, Siberia).

Discussion

Plants of Draba oblongata are occasionally misidentified as decaploid (2n = 80) D. arctica, but the former is readily separated by a preponderance of simple (versus stellate) trichomes on both leaf blade surfaces. Draba oblongata is sometimes confused with D. micropetala, but the latter has pale yellow (versus white) flowers, fruits pubescent with simple and spurred (versus (2–)5–12-rayed) trichomes, and stigmas as wide as (versus much wider than) the style.

Selected References

None.

Lower Taxa