Draba cana |
Draba kluanei |
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Brewer's Draba, canescent Draba, canescent whitlow-mustard, cushion Draba, hoary Draba, hoary whitlow-grass, lance-leaf Draba, lance-leaf whitlow-grass |
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Habit | Perennials; caudex simple or branched (branches short); not scapose. | Perennials; (cespitose); caudex branched (with persistent leaf remains); not scapose. |
Stems | unbranched or branched distally, (0.6–)1–3(–3.8) dm, pubescent throughout, trichomes simple, 0.5–1mm, with 4–10-rayed ones, 0.05–0.2 mm (mostly branched on basal parts). |
unbranched, 0.1–0.35 dm, pilose throughout, trichomes simple, (slightly crisped), 0.4–0.9 mm. |
Basal leaves | rosulate; petiolate; petiole ciliate throughout; blade linear to oblanceolate or oblong, (0.5–)0.8–2(–3.5) cm × 1.5–4(–11) mm, margins entire or dentate, (base and apex ciliate, trichomes simple, 0.3–0.8 mm), surfaces pubescent with short-stalked, 4–12-rayed trichomes, 0.1–0.3 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 | 3–10(–17), (not overlapping); sessile; blade lanceolate to ovate or oblong, margins entire or dentate, surfaces pubescent as basal (adaxially with simple and forked trichomes near blade base). |
1–3; sessile; blade lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | (10–)15–47(–63)-flowered, basally bracteate, often considerably elongated in fruit; rachis not flexuous, densely pubescent, trichomes 4–10-rayed (0.05–0.2 mm), and fewer simple ones. |
2–7-flowered, ebracteate or proximalmost 1 or 2 flowers bracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
Flowers | sepals (green or lavender), oblong to ovate, 1.5–2 mm, pubescent, (trichomes simple and few-rayed); petals white, oblanceolate to spatulate, 2.3–3.7(–4.5) × 0.7–1.7 mm; anthers ovate, 0.1–0.2 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 | suberect or ascending, straight, 2–5(–10) mm, pubescent as rachis. |
divaricate-ascending, straight, 1–2 mm, glabrous. |
Fruits | (subappressed to rachis), linear-lanceolate to linear or, rarely, ovate-oblong, slightly twisted or plane, flattened, (5–)6–11 × 1.5–2(–2.5) mm; valves pubescent, trichomes short-stalked, 3–7-rayed, 0.05–0.3 mm; ovules 28–48 per ovary; style 0.1–0.6 mm. |
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 | ovoid, 0.5–0.7(–0.9) × 0.3–0.5 mm. |
oblong, ca. 0.6 × 0.4 mm. |
2n | = 32. |
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Draba cana |
Draba kluanei |
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Phenology | Flowering (May-)Jun–Aug. | Flowering Jul. |
Habitat | Rock outcrops and talus, open prairie benchlands, roadsides, meadows, alpine tundra | Rocky alpine slopes |
Elevation | 0-4100 m (0-13500 ft) | ca. 2000 m (ca. 6600 ft) |
Distribution |
AK; CA; CO; ID; ME; MI; MT; NH; NM; NV; SD; UT; VT; WA; WI; WY; AB; BC; MB; NB; NF; NT; ON; QC; SK; YT; Greenland
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YT |
Discussion | The limits of Draba cana have long been confused, and the species was treated as a synonym of the Himalayan D. lanceolata Royle (M. L. Fernald 1934; C. L. Hitchcock 1941) or as a variety of the western North American D. breweri (R. C. Rollins 1993). However, G. A. Mulligan (1971) clearly demonstrated that all three are distinct and should be maintained. Some Utah plants corresponding to the type of D. valida have shorter and wider oblong-ovate fruits. In all other aspects, they are indistinguishable from D. cana. Additional studies are needed to establish whether such plants should be formally recognized. (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. 298. | FNA vol. 7, p. 315. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. breweri var. cana, D. valida | |
Name authority | Rydberg: Bull. Torrey Bot. Club 29: 241. (1902) | G. A. Mulligan: Canad. J. Bot. 57: 1873. (1979) |
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