Draba monoensis |
Draba cana |
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Mono Draba, White Mountains Draba |
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; (usually cespitose); caudex simple or branched (poorly developed, with persistent leaf remains); sometimes scapose. | Perennials; caudex simple or branched (branches short); not scapose. |
Stems | unbranched, (0.05–)0.1–0.4 dm, usually pubescent throughout, rarely sparsely pubescent or glabrous distally, trichomes simple and 2-rayed, (often crisped), 0.1–0.6 mm. |
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). |
Basal leaves | rosulate; subsessile or shortly petiolate; petiole margin ciliate or not; blade narrowly oblanceolate, (0.3–)0.5–1.6(–2) cm × (1–)1.5–3(–4) mm, margins usually entire, rarely subapically denticulate, (ciliate or not), surfaces pubescent with simple and stalked, 2-rayed trichomes, 0.1–0.7 mm, (midvein obscure abaxially). |
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. |
Cauline leaves | 0–2 (or 3); sessile; blade ovate to oblong, margins entire, surfaces pubescent as basal. |
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). |
Racemes | (3–)6–13(–17)-flowered, ebracteate or proximalmost 1 (or 2) flowers bracteate, not or slightly elongated in fruit; rachis not flexuous, usually pubescent as stem, rarely glabrous. |
(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. |
Flowers | sepals (persistent), oblong, 1–1.5 mm, subapically sparsely pubescent, (trichomes simple); petals white, spatulate, 1.5–2 × 0.5–0.6 mm; anthers ovate, 0.15–0.2 mm. |
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. |
Fruiting pedicels | divaricate-ascending, straight, 1–2.5(–4) mm, usually pubescent as stem, rarely glabrous. |
suberect or ascending, straight, 2–5(–10) mm, pubescent as rachis. |
Fruits | ovoid to subellipsoid, plane, slightly inflated basally, (2–)3–5 × (1.2–)1.5–2.5 mm; valves usually puberulent, rarely glabrous, trichomes simple, 0.05–0.2 mm; ovules 12–20 per ovary; style 0.1–0.2 mm. |
(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. |
Seeds | ovoid, 0.6–0.8 × 0.4–0.6 mm. |
ovoid, 0.5–0.7(–0.9) × 0.3–0.5 mm. |
2n | = 32. |
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Draba monoensis |
Draba cana |
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Phenology | Flowering Jul–Aug. | Flowering (May-)Jun–Aug. |
Habitat | Gravelly alpine meadows | Rock outcrops and talus, open prairie benchlands, roadsides, meadows, alpine tundra |
Elevation | 3600-4000 m (11800-13100 ft) | 0-4100 m (0-13500 ft) |
Distribution |
CA |
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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Discussion | Of conservation concern. Draba monoensis appears to be polyploid (M. D. Windham, unpubl.), and its morphological similarity to D. fladnizensis (R. C. Rollins 1993) may indicate that the latter is one of its progenitors. The species is known from the White Mountains of Mono County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 320. | FNA vol. 7, p. 298. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. breweri var. cana, D. valida | |
Name authority | Rollins & R. A. Price: Aliso 12: 22, figs. 1f–j, 3. (1988) | Rydberg: Bull. Torrey Bot. Club 29: 241. (1902) |
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