Draba praealta |
Draba ruaxes |
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Draba, tall Draba, tall whitlow-grass, tall whitlow-grass Draba |
coast mountain Draba, coast mountain whitlow-grass, coast mountain whitlow-grass Draba, Rainier Draba |
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Habit | Annuals or perennials; (short-lived); caudex simple or branched; not scapose. | Perennials; (cespitose, forming tufts); caudex branched (with persistent leaf bases, branches some 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, 0.2–0.6(–0.8) dm, often pubescent throughout, sometimes glabrate distally, trichomes simple, 0.4–1 mm, and 2–4-rayed, 0.1–0.4 mm. |
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; 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). |
Cauline leaves | (1 or) 2–5(–9); sessile; blade ovate to lanceolate, margins dentate or entire, surfaces pubescent as basal. |
0. |
Racemes | (5–)8–30(–37)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
(2–)4–10(–14)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem or 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 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. |
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. |
ascending to divaricate-ascending, straight or slightly curved upward, 3–7(–9) mm, pubescent or glabrous, trichomes simple and 2–4-rayed. |
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. |
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. |
Seeds | oblong, 0.8–1.1 × 0.5–0.6 mm, (often apiculate). |
oblong, 1.5–2 × 1–1.3 mm. |
2n | = 56. |
= 72. |
Draba praealta |
Draba ruaxes |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Rocky pine slopes, subalpine areas, alpine meadows, grassy volcanic ridges, woodlands, damp rocky areas, limestone talus, shale cliffs, steep hillsides | Rock outcrops, talus slopes, ridges, alpine summits |
Elevation | 1200-2900 m (3900-9500 ft) | 500-2400 m (1600-7900 ft) |
Distribution |
CA; ID; MT; NV; OR; WA; WY; AB; BC; NT; YT; e Asia (Russian Far East [Chukchi Peninsula])
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AK; WA; AB; BC; YT
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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) 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.) |
Source | FNA vol. 7, p. 331. | FNA vol. 7, p. 334. |
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. ventosa var. ruaxes |
Name authority | Greene: Pittonia 3: 306. (1898) | Payson & H. St. John: Proc. Biol. Soc. Wash. 43: 117. (1930) |
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