Draba corymbosa |
Draba kluanei |
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Baffin bay Draba, Baffin bay whitlow-grass, flat-top Draba |
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Habit | Perennials; (cespitose); caudex branched (with persistent leaves or leaf remains, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose); caudex branched (with persistent leaf remains); not 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, 0.1–0.35 dm, pilose throughout, trichomes simple, (slightly crisped), 0.4–0.9 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; petiolate; petiole base and margin ciliate, (trichomes usually simple, rarely some 2-rayed, 0.2–0.7 mm); blade oblanceolate to linear-oblanceolate, 0.6–1.5 cm × 0.5–2 mm, margins entire or sparsely dentate, surfaces pubescent, abaxially with simple trichomes, 0.3–0.9 mm, with fewer, 2(or 3)-rayed ones, 0.07–0.3 mm, adaxially with simple trichomes. |
Cauline leaves | 0. |
1–3; sessile; blade lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | 2–9(–12)-flowered, ebracteate, (corymbose), slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
2–7-flowered, ebracteate or proximalmost 1 or 2 flowers bracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
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 ovate, 0.7–1.3 mm, subapically sparsely pubescent, (trichomes simple); petals white, spatulate, 1.5–2 × 0.4–0.8 mm; anthers ovate, 0.2–0.3 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved upward, 4–11(–16) mm, pubescent, trichomes simple and 2–4-rayed. |
divaricate-ascending, straight, 1–2 mm, glabrous. |
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, plane, flattened, 3–4 × 1–1.5 mm; valves pubescent, trichomes simple, 0.7–0.2 mm; ovules 14–16 per ovary; style 0.1–0.25 mm. |
Seeds | (brown), ovoid, 1–1.3 × 0.6–0.9 mm. |
oblong, ca. 0.6 × 0.4 mm. |
2n | = 128, 144. |
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Draba corymbosa |
Draba kluanei |
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Phenology | Flowering Jun–Aug. | Flowering Jul. |
Habitat | Moist tundra, among calcareous or dolomitic rocks, gravel beaches, silt and clay terraces | Rocky alpine slopes |
Elevation | 0-1700 m (0-5600 ft) | ca. 2000 m (ca. 6600 ft) |
Distribution |
AK; BC; NT; NU; YT; Greenland; Europe (Norway, n Russia); e Asia (Russian Far East, Siberia) |
YT |
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.) |
Of conservation concern. Draba kluanei is known only from the type collection made in Kluane National Park, southwestern Yukon Territory. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 301. | FNA vol. 7, p. 315. |
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 | |
Name authority | R. Brown ex de Candolle: Syst. Nat. 2: 343. (1821) | G. A. Mulligan: Canad. J. Bot. 57: 1873. (1979) |
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