Draba corymbosa |
Draba californica |
|
---|---|---|
Baffin bay Draba, Baffin bay whitlow-grass, flat-top Draba |
California Draba |
|
Habit | Perennials; (cespitose); caudex branched (with persistent leaves or leaf remains, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (short-lived); caudex simple or branched; sometimes scapose. |
Stems | unbranched, (0.05–)0.2–0.8(–1.5) dm, pubescent throughout, trichomes simple and 2-rayed, 0.4–1 mm, with 3–5-rayed ones, 0.05–0.4 mm, (sometimes trichomes mostly simple). |
unbranched or branched (few), (0.2–)0.4–0.9(–1.2) dm, pubescent throughout, trichomes stellate, 4–8-rayed, 0.05–0.5 mm. |
Basal leaves | rosulate; petiolate; petiole base and margin ciliate, (trichomes often course, simple, 0.4–1.3 mm); blade oblanceolate to obovate, 0.6–1.8 cm × 1.5–5 mm, margins entire, surfaces pubescent, abaxially with stalked, 2–6-rayed trichomes, 0.2–0.6 mm, adaxially with primarily simple and stalked, 2-rayed trichomes, to 1.1 mm, with 3–5-rayed ones, 0.2–0.4 mm. |
rosulate; shortly petiolate; petiole ciliate, margin not ciliate, (trichomes simple and 2-rayed, 0.3–1 mm); blade oblanceolate, 0.6–2 cm × 1.5–4(–6) mm, margins entire, surfaces pubescent with short-stalked, 4–8-rayed trichomes, 0.1–0.4 mm. |
Cauline leaves | 0. |
0–3; sessile; blade ovate to oblong, margins entire, surfaces pubescent as basal. |
Racemes | 2–9(–12)-flowered, ebracteate, (corymbose), slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
3–13-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals (grayish green), broadly ovate, 2.2–3 mm, pubescent, (trichomes simple, to 1 mm, sometimes with stalked, smaller, 2–4-rayed ones); petals (broadly patent), yellow, obovate, 4–6 × 3–5 mm; anthers ovate, 0.3–0.4 mm. |
sepals (persistent until fruit maturity), oblong to ovate, 1.7–2.5 mm, pubescent, (trichomes short-stalked, 2–5-rayed); petals white or creamy white, spatulate to oblanceolate, 2.2–3 × 0.8–1 mm; anthers ovate, 0.2–0.35 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved upward, 4–11(–16) mm, pubescent, trichomes simple and 2–4-rayed. |
ascending to divaricate-ascending, straight, (2–)4–9(–12) mm, pubescent, trichomes short-stalked, 4–8-rayed, (0.1–0.4 mm). |
Fruits | oblong or ovate, plane, flattened, 6–12 × 3.5–5.5 mm; valves pubescent or puberulent, trichomes simple, 0.1–0.4 mm, (sometimes with short-stalked, 2- or 3-rayed ones); ovules 12–24 per ovary; style 0.6–1 mm (stigma distinctly wider than style). |
lanceolate to oblong, plane, slightly flattened, (5–)6–9(–11) × 1.8–2.5 mm; valves usually pubescent, rarely glabrous, trichomes simple and short-stalked, 2- or 3-rayed, 0.05–0.25 mm; ovules 22–32 per ovary; style 0.1–0.3(–0.4) mm. |
Seeds | (brown), ovoid, 1–1.3 × 0.6–0.9 mm. |
oblong, 0.8–1 × 0.5–0.6 mm. |
2n | = 128, 144. |
|
Draba corymbosa |
Draba californica |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Moist tundra, among calcareous or dolomitic rocks, gravel beaches, silt and clay terraces | Grassy meadows, alpine areas, fellfields |
Elevation | 0-1700 m (0-5600 ft) | 3200-4000 m (10500-13100 ft) |
Distribution |
AK; BC; NT; NU; YT; Greenland; Europe (Norway, n Russia); e Asia (Russian Far East, Siberia) |
CA; NV |
Discussion | Draba corymbosa, which is 16-ploid or 18-ploid with x = 8, is an extremely variable species of polyphyletic, allopolyploid origin. Most individuals appear to have decaploid D. alpina (2n = 80) in their parentage, but the other genomes are provided by hexaploid (2n = 48) and octoploid (2n = 64) species (C. Brochmann et al. 1993). O. E. Schulz reduced D. corymbosa to a variety of D. alpina; R. C. Rollins (1993) treated it as a distinct species. Draba corymbosa is distinguished from D. alpina by having pubescent or puberulent (versus glabrous or glabrescent) fruits, corymbose (versus usually elongated) fruiting racemes, and abaxial leaf blade surfaces always lacking (versus usually with some) simple trichomes. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Although originally treated as a variety of Draba cuneifolia, D. californica is but distantly related to that species. Instead, ongoing studies (L. Allphin and M. D. Windham, unpubl.) suggest that it may be an allopolyploid resulting from hybridization between D. albertina and D. breweri. The species is restricted to the White Mountains in Mono County, California, and adjacent Esmeralda County, Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 301. | FNA vol. 7, p. 298. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. bellii, D. alpina var. corymbosa, D. barbata, D. bellii, D. kjellmanii, D. macrocarpa, D. vestita | D. cuneifolia var. californica |
Name authority | R. Brown ex de Candolle: Syst. Nat. 2: 343. (1821) | (Jepson) Rollins & R. A. Price: Aliso 12: 19. (1988) |
Web links |