Draba ruaxes |
Draba abajoensis |
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coast mountain Draba, coast mountain whitlow-grass, coast mountain whitlow-grass Draba, Rainier Draba |
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Habit | Perennials; (cespitose, forming tufts); caudex branched (with persistent leaf bases, branches some terminating in sterile rosettes); scapose. | Perennials; caudex simple or branched, (sometimes with persistent leaf bases); 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. |
unbranched, (0.6–)1–2.5(–3.5) dm, pubescent proximally, usually glabrous distally, rarely sparsely pubescent, trichomes simple, 0.1–0.5 mm, often with stalked, 2(–4)-rayed ones. |
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; petiolate; petiole (0.2–1(–2) cm), proximal margin ciliate, (trichomes simple, 0.2–0.7 mm); blade oblanceolate to spatulate, (0.6–)1–3.5(–4.3) cm × (2–)4–10(–14) mm, margins entire or dentate, surfaces pubescent with short-stalked, (2–)4-rayed trichomes, 0.05–0.35 mm, sometimes adaxially with simple ones. |
Cauline leaves | 0. |
(3–)5–9(–11); sessile; blade broadly ovate to lanceolate or oblong, margins entire or dentate, surfaces pubescent as basal or adaxially also with mostly simple trichomes. |
Racemes | (2–)4–10(–14)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem or glabrous. |
(11–)15–32(–47)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent, trichomes simple and short-stalked, 2–4-rayed. |
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. |
sepals ovate-oblong, 2.2–3.5 mm, subapically sparsely pubescent, (trichomes simple, short-stalked, and 2-rayed); petals yellow, oblanceolate, 4–6 × 1.5–2 mm; anthers oblong, 0.6–1 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. |
horizontal to divaricate-ascending, straight or curved, (5–)7–18(–23) mm, glabrous or sparsely pubescent abaxially, trichomes simple and 2-rayed. |
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. |
elliptic to elliptic-lanceolate, plane, flattened, 5–9(–12) × 2–3 mm; valves glabrous; ovules 10–18 per ovary; style (0.8–)1.4–2.7(–3.6) mm. |
Seeds | oblong, 1.5–2 × 1–1.3 mm. |
ovoid, 1–1.2 × 0.7–0.8 mm. |
2n | = 72. |
= 20. |
Draba ruaxes |
Draba abajoensis |
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Phenology | Flowering Jun–Jul. | Flowering May–Aug. |
Habitat | Rock outcrops, talus slopes, ridges, alpine summits | Spruce, fir, or pine forests, subalpine meadows |
Elevation | 500-2400 m (1600-7900 ft) | 1900-3800 m (6200-12500 ft) |
Distribution |
AK; WA; AB; BC; YT
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AZ; NM; UT |
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.) |
Plants of Draba abajoensis were treated by C. L. Hitchcock (1941), R. C. Rollins (1993), and N. H. Holmgren (2005b) as D. spectabilis. The differences between these taxa in chromosome number and trichome morphology strongly support their recognition as separate species (I. A. Al-Shehbaz and M. D. Windham 2007). Draba abajoensis has been collected from the Chuska and Lukachukai mountains in Apache County, Arizona, Chuska Mountains in San Juan County, New Mexico, and Abajo and La Sal mountains in San Juan and Grand counties, Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 334. | FNA vol. 7, p. 288. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. ventosa var. ruaxes | D. spectabilis var. glabrescens |
Name authority | Payson & H. St. John: Proc. Biol. Soc. Wash. 43: 117. (1930) | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 416. (2007) |
Web links |