Draba praealta |
Draba asterophora |
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Draba, tall Draba, tall whitlow-grass, tall whitlow-grass Draba |
Lake Tahoe Draba, Tahoe Draba |
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Habit | Annuals or perennials; (short-lived); caudex simple or branched; not scapose. | Perennials; (loosely cespitose); caudex branched (somewhat surculose, with persistent leaf bases, branches sometimes terminating in sterile rosettes); scapose. |
Stems | branched or unbranched, (0.5–)0.8–3.2(–3.8) dm, pubescent throughout, trichomes 3–5-rayed, 0.1–0.4 mm, with simple and 2-rayed ones, 0.4–1 mm. |
unbranched, 0.3–1.1 dm, glabrous throughout or sparsely pubescent proximally, trichomes (2–)4-rayed, 0.1–0.3 mm. |
Basal leaves | rosulate; subsessile; petiole base ciliate, (trichomes simple and 2-rayed, 0.2–0.8 mm); blade oblanceolate, (0.7–)1–3.5(–4.5) cm × 1.5–7(–9) mm, margins usually dentate, rarely entire, surfaces pubescent, abaxially with stalked, 3–6-rayed trichomes, 0.1–0.5 mm, adaxially with stalked, 3–5-rayed, 0.1–0.6 mm, and simple ones, to 0.8 mm. |
rosulate; petiolate; petiole obsolete, margin rarely ciliate proximally; blade (somewhat fleshy), broadly obovate to suborbicular or spatulate, 0.4–1.4(–1.7) cm × (2–)3–6(–7) mm, margins entire, surfaces pubescent, trichomes stalked, cruciform, and 2-, 3-, or 5-rayed, 0.2–0.6 mm. |
Cauline leaves | (1 or) 2–5(–9); sessile; blade ovate to lanceolate, margins dentate or entire, surfaces pubescent as basal. |
0 (or 1, as a bract). |
Racemes | (5–)8–30(–37)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
(5–)8–20(–27)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, elongated in fruit; rachis not flexuous, glabrous. |
Flowers | (late-season ones petaliferous); sepals ovate, 1.7–2.5 mm, pubescent, (trichomes simple and stalked, 2-rayed); petals white, oblanceolate to spatulate, 2.8–3.5(–4) × 0.8–1.2 mm; anthers ovate, 0.2–0.3 mm. |
sepals oblong, 3–4 mm, glabrous or sparsely pubescent, (trichomes subapical, short-stalked, 2–4-rayed); petals bright yellow, oblanceolate, 5–7 × 1.5–2.5 mm; anthers ovate, 0.5–0.6 mm. |
Fruiting pedicels | divaricate-ascending to ascending or suberect (not appressed to rachis), straight, (3–)4–10(–12) mm, pubescent, trichomes 3–5-rayed (0.1–0.4 mm), and sometimes simple. |
horizontal to divaricate-ascending, straight or curved upward, 3–9 mm, glabrous. |
Fruits | (erect, not appressed to rachis) lanceolate to linear-lanceolate, plane, flattened, (5–)7–12(–15) × 1.5–2.5(–3) mm; valves puberulent, trichomes simple and short-stalked, 2–4-rayed, 0.05–0.25 mm; ovules (24–)30–52 per ovary; style 0.03–0.1(0.15) mm. |
lanceolate-ovate to broadly ovate or oblong, slightly twisted or plane, strongly flattened, 5–11(–14) × (3.5–)4–6 mm; valves glabrous or, rarely, puberulent, trichomes simple and short-stalked, 2- or 3-rayed, 0.05–0.3 mm; ovules 12–18 per ovary; style 0.2–1.6(–2) mm. |
Seeds | oblong, 0.8–1.1 × 0.5–0.6 mm, (often apiculate). |
(winged), ovate, 1.8–2.8 × 1.2–2 mm; (wing 0.5–1 mm wide). |
2n | = 56. |
= 40. |
Draba praealta |
Draba asterophora |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Rocky pine slopes, subalpine areas, alpine meadows, grassy volcanic ridges, woodlands, damp rocky areas, limestone talus, shale cliffs, steep hillsides | Granitic rock outcrops, talus, gravelly soil |
Elevation | 1200-2900 m (3900-9500 ft) | 2600-3300 m (8500-10800 ft) |
Distribution |
CA; ID; MT; NV; OR; WA; WY; AB; BC; NT; YT; e Asia (Russian Far East [Chukchi Peninsula])
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CA; NV |
Discussion | Morphological and chromosomal evidence (M. D. Windham, unpubl.) suggests that Draba praealta may be an allopolyploid originating through hybridization between D. albertina and D. cana. Both R. C. Rollins (1993) and N. H. Holmgren (2005b) placed D. lonchocarpa var. dasycarpa in the synonymy of D. lonchocarpa. G. A. Mulligan (1974) indicated that the type of var. dasycarpa does not belong to that species and he correctly annotated its isotype (Macoun 64454, CAN) as D. praealta. Mulligan (1976) and Rollins indicated that D. praealta occurs in Alaska, but we have not seen unequivocal material from the state. We have not seen the material on which A. E. Katenin and V. V. Petrovsky (1995) based their record from the Russian Far East. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
C. L. Hitchcock (1941) and R. C. Rollins (1993) divided Draba asterophora into two varieties based on minor differences in style and fruit lengths. These do not appear to define genetically discrete taxa. The species apparently is restricted to El Dorado County, California, and the Carson Range in Washoe County, Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 331. | FNA vol. 7, p. 294. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. cascadensis, D. columbiana, D. dolichopoda, D. lapilutea, D. lonchocarpa var. dasycarpa, D. praealta var. yellowstonensis, D. yellowstonensis | D. asterophora var. macrocarpa |
Name authority | Greene: Pittonia 3: 306. (1898) | Payson: Amer. J. Bot. 4: 263. (1917) |
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