Draba aureola |
Draba brachycarpa |
|
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alpine whitlow-grass, golden alpine Draba, golden Draba, great alpine whitlow-grass, Mt. Lassen Draba, Mt. Lassen Draba whitlow-grass, Mt. Lassen whitlow-grass |
short-pod whitlowgrass, shortfruit Draba, shortpod Draba |
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Habit | Perennials; (short-lived); caudex simple or branched (poorly developed, with persistent dry leaves); not scapose. | Annuals; not scapose. |
Stems | unbranched or branched, 0.3–1.5 dm, hirsute throughout, trichomes simple and long-stalked, 2–4-rayed, 0.2–1.5 mm. |
usually branched, rarely unbranched, (0.3–)0.4–1.9(–2.2) dm, pubescent throughout, trichomes sessile, cruciform, 0.2–0.6(–0.8) mm (rays often equal, or those parallel to stem axis longer). |
Basal leaves | (forming dense clusters); rosulate; sessile; blade oblanceolate to linear, (0.7–)1–2.5(–3.2) cm × 2–3.5(–5) mm, margins entire, (ciliate, trichomes simple and 2-rayed, 0.5–1.5 mm), surfaces densely hirsute, abaxially with stalked, 3–5-rayed trichomes, 0.1–0.5 mm, adaxially with simple and long-stalked, 2-rayed trichomes, to 1 mm, with smaller, 3–5-rayed ones. |
not rosulate; petiolate; petiole (to 0.5 cm), not ciliate; blade oblanceolate to obovate, 0.5–2 cm × 2–8 mm, margins entire, surfaces pubescent, trichomes cruciform, 0.2–0.6(–0.8) mm. |
Cauline leaves | 5–33; sessile; blade oblong to linear, margins entire, surfaces pubescent as basal. |
(4–)6–11; sessile; blade lanceolate to oblong or linear, margins entire, surfaces pubescent as basal. |
Racemes | 12–83-flowered, ebracteate or proximalmost 1–9 flowers bracteate, slightly or not elongated in fruit; rachis not flexuous, hirsute as stem. |
(main branch) (20–)25–65(–74)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals ovate, 2.5–4 mm, glabrous; petals bright yellow, linear to linear-oblanceolate, 4–6 × 0.5–1(–1.2) mm; anthers narrowly oblong, 0.8–1 mm. |
(late ones cleistogamous, apetalous); sepals (green or pink), oblong, 0.7–1.2(–1.5) mm, pubescent; petals white, spatulate, 2–3 × 0.8–1.1 mm; anthers ovate, 0.15–0.25 mm. |
Fruiting pedicels | horizontal to divaricate, usually straight, rarely curved upward, (3–)5–12(–19) mm, hirsute as stem. |
horizontal to divaricate-ascending, straight, (1–)1.5–4(–5) mm, pubescent, trichomes cruciform. |
Fruits | oblong or, rarely, oblong-ovate, plane, flattened, (6–)9–14(–16) × 3–5 mm; valves pubescent, trichomes stalked, 2–4-rayed, 0.07–0.5 mm; ovules 10–20 per ovary; style (0.6–)1–1.6(–2) mm. |
usually elliptic to linear-elliptic, rarely ovate-elliptic, plane, flattened, (2–)2.5–5(–6) × 0.9–1.4(–1.9) mm; valves glabrous; ovules 8–16(–20) per ovary; style 0.05–0.1 mm. |
Seeds | oblong, 1.4–1.9 × 0.8–1.1 mm. |
(winged), ovoid, 0.5–0.7 × 0.4–0.5 mm. |
2n | = 20. |
= 16. |
Draba aureola |
Draba brachycarpa |
|
Phenology | Flowering Jul–Aug. | Flowering Feb–May. |
Habitat | Open conifer forests, alpine meadows and moraines, talus slopes | Open woods, cedar glades, pastures and lawns, roadsides, disturbed sites |
Elevation | 2200-3200 m (7200-10500 ft) | 0-300 m (0-1000 ft) |
Distribution |
CA; OR; WA
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AL; AR; AZ; FL; GA; IL; IN; KS; KY; LA; MO; MS; NC; OH; OK; OR; SC; TN; TX; VA
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Discussion | Draba aureola is known from Lassen, Shasta, and Siskiyou counties in California, Deschutes County in Oregon, and Lewis and Pierce counties in Washington. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba brachycarpa is closely related to D. aprica and the two are sometimes confused. It is readily distinguished by having leaves with sessile (versus stalked) trichomes, glabrous (versus pubescent) fruits, and smaller (0.5–0.7 versus 0.9–1.1 mm) seeds. The records from Arizona and Oregon are based on old collections, Porter 802 (Devil’s Canyon, 22 Feb 1926, US) and Howell s.n. (near Cobarg, Willamette Valley, 7 Apr 1887, US); it is not known if these records represent introductions or remnants of a previously wider distribution. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 295. | FNA vol. 7, p. 296. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. aureola var. paniculata | Abdra brachycarpa |
Name authority | S. Watson: in W. H. Brewer et al., Bot. California 2: 430. (1880) | Nuttall ex Torrey & A. Gray: Fl. N. Amer. 1: 108. (1838) |
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