Draba ruaxes |
Draba praealta |
|
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coast mountain Draba, coast mountain whitlow-grass, coast mountain whitlow-grass Draba, Rainier Draba |
Draba, tall Draba, tall whitlow-grass, tall whitlow-grass Draba |
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Habit | Perennials; (cespitose, forming tufts); caudex branched (with persistent leaf bases, branches some terminating in sterile rosettes); scapose. | Annuals or perennials; (short-lived); caudex simple or branched; not scapose. |
Stems | unbranched, 0.2–0.6(–0.8) dm, often pubescent throughout, sometimes glabrate distally, trichomes simple, 0.4–1 mm, and 2–4-rayed, 0.1–0.4 mm. |
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. |
Basal leaves | rosulate; subsessile; petiole base and margin ciliate, (trichomes simple, 0.4–1.4 mm); blade oblanceolate to obovate or suborbicular, 0.3–1 cm × 2–4.5 mm, margins entire, surfaces pubescent, abaxially with stalked, 2–10-rayed, stellate trichomes, 0.2–0.8 mm, adaxially with simple trichomes, 0.4–1 mm, sometimes with smaller, 2–4-rayed ones, (midvein obscure). |
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. |
Cauline leaves | 0. |
(1 or) 2–5(–9); sessile; blade ovate to lanceolate, margins dentate or entire, surfaces pubescent as basal. |
Racemes | (2–)4–10(–14)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem or glabrous. |
(5–)8–30(–37)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals ovate, 2–3 mm, pubescent, (trichomes simple with fewer, 2-rayed ones); petals bright yellow, obovate, 4–6 × 2–3.5 mm; anthers oblong, 0.4–0.5 mm. |
(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. |
Fruiting pedicels | ascending to divaricate-ascending, straight or slightly curved upward, 3–7(–9) mm, pubescent or glabrous, trichomes simple and 2–4-rayed. |
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. |
Fruits | elliptic to lanceolate or ovate to suborbicular, plane, flattened, 4–8(–10) × 3–4.5 mm; valves puberulent, trichomes simple with fewer 2-rayed ones, 0.1–0.35 mm; ovules 12–16 per ovary; style 0.5–0.9(–1.1) mm. |
(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. |
Seeds | oblong, 1.5–2 × 1–1.3 mm. |
oblong, 0.8–1.1 × 0.5–0.6 mm, (often apiculate). |
2n | = 72. |
= 56. |
Draba ruaxes |
Draba praealta |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Aug. |
Habitat | Rock outcrops, talus slopes, ridges, alpine summits | Rocky pine slopes, subalpine areas, alpine meadows, grassy volcanic ridges, woodlands, damp rocky areas, limestone talus, shale cliffs, steep hillsides |
Elevation | 500-2400 m (1600-7900 ft) | 1200-2900 m (3900-9500 ft) |
Distribution |
AK; WA; AB; BC; YT
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CA; ID; MT; NV; OR; WA; WY; AB; BC; NT; YT; e Asia (Russian Far East [Chukchi Peninsula])
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Discussion | C. L. Hitchcock (1941) treated Draba ruaxes as a variety of D. ventosa; as demonstrated by G. A. Mulligan (1971b), the two are quite distinct. Draba ruaxes is an outcrossing hexaploid with well-formed anthers and pollen, and abundant, simple trichomes on leaves, stems, sepals, and fruits. By contrast, D. ventosa is an apomictic triploid with abortive anthers and/or pollen, and no simple trichomes anywhere on the plant. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 334. | FNA vol. 7, p. 331. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. ventosa var. ruaxes | D. cascadensis, D. columbiana, D. dolichopoda, D. lapilutea, D. lonchocarpa var. dasycarpa, D. praealta var. yellowstonensis, D. yellowstonensis |
Name authority | Payson & H. St. John: Proc. Biol. Soc. Wash. 43: 117. (1930) | Greene: Pittonia 3: 306. (1898) |
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