Draba nemorosa

Annuals; not scapose. Stems unbranched or branched proximally, (0.3–)0.6–4.5(–6) dm, densely pubescent proximally, glabrous distally, trichomes simple, 0.5–1.3 mm, and stalked, 2–4-rayed, 0.1–0.5 mm. Basal leaves rosulate or not, petiolate; petiole ciliate throughout; blade oblong-obovate or oblanceolate, (0.4–)1–3.5(–5) cm × (2–)5–15(–20) mm, margins usually dentate to denticulate, rarely subentire, surfaces sparsely to densely pubescent with stalked, 2- or 3-rayed, and cruciform trichomes, 0.1–0.5 mm. Cauline leaves 4–12(–15); sessile; blade broadly ovate to oblong, margins dentate or denticulate, surfaces pubescent, abaxially as basal, adaxially with primarily simple, and 2- or 3-rayed trichomes. Racemes (10–)18–60(–92)-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous (straight), glabrous. Fruiting pedicels divaricate, straight, 7–28(–35) mm [(1.5–)2–7 times longer than fruit], glabrous. Flowers: sepals ovate, (0.7–)0.9–1.6 mm, sparsely pubescent, (trichomes simple); petals yellow, spatulate to oblanceolate, (1.2–)1.7–2.2(–2.5) × (0.4–)0.6–1 mm, (deeply notched); anthers broadly ovate to subreniform, 0.1–0.2 mm. Fruits oblong to elliptic or, rarely, oblong-oblanceolate, plane, slightly flattened, (3–)5–8 (–10) × 1.5–2.5 mm; valves glabrous or puberulent, trichomes simple, antrorse, 0.05–0.2 mm; ovules (30–)36–60(–72) per ovary; style 0.01–0.1 mm. Seeds ovoid, 0.5–0.7(–0.8) × 0.3–0.4(–0.5) mm. 2n = 16.

Phenology: Flowering Apr–Jul.
Habitat: Rock outcrops, open wooded slopes, meadows and prairies, stream banks, roadsides, disturbed gravelly grounds, waste places
Elevation: 0-2700 m

Introduced; Alta., B.C., Man., N.W.T., Nunavut, Ont., Que., Sask., Yukon, Alaska, Calif., Colo., Idaho, Iowa, Mich., Minn., Mont., Nebr., Nev., N.Dak., Oreg., S.Dak., Utah, Wash., Wis., Wyo., Europe, Asia, introduced also in Australia.

Discussion

Selected References

None.

Lower Taxa