Draba kassii |
Draba arctica |
|
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kass' Draba |
arctic whitlowgrass |
|
Habit | Perennials; caudex branched (densely covered with persistent petiole remains, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose, not pulvinate); caudex simple or branched; rarely scapose. |
Stems | unbranched, 0.5–1.8 dm, glabrous. |
unbranched, 0.3–1.7(–2.4) dm, pubescent, trichomes 4–10-rayed (rays sometimes branched), 0.1–0.3 mm, with fewer, simple ones, to 0.7 mm. |
Basal leaves | rosulate; long-petiolate; petiole ciliate throughout; blade oblanceolate to linear-oblanceolate, 1.5–5.5 cm × (1.5–)2–5.5 mm, margins entire (ciliate, trichomes simple, 0.2–1 mm), surfaces abaxially sparsely pubescent with short-stalked, submalpighiaceous trichomes, 0.3–1.3 mm, sometimes with 3- or 4-rayed ones, adaxially usually glabrous, rarely sparsely pubescent. |
rosulate; petiolate; petiole base ciliate, (trichomes simple, 0.2–0.8 mm); blade oblanceolate to narrowly obovate, 0.4–2.3(–3) cm × 1.5–6.5 mm, margins usually entire, rarely with 1 tooth on each side, surfaces densely pubescent with minutely stalked, 8–12-rayed, stellate trichomes, 0.2–0.4 mm, sometimes with coarser, simple or 2-rayed ones, (midvein distinct abaxially). |
Cauline leaves | 0. |
0 or 1(–3); sessile; blade ovate or oblong to lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | 3–8(–10)-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, glabrous. |
3–18(–25)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals broadly ovate, 2–3 mm, subapically sparsely pubescent, (trichomes simple); petals yellow, oblanceolate, 4.5–7 × 1.2–2 mm; anthers ovate, 0.4–0.5 mm. |
sepals ovate, 2–2.5 mm, pubescent, (trichomes short-stalked, 2- or 3-rayed, and simple); petals white, spatulate to obovate, 3.5–6 × 1.8–2 mm; anthers ovate, 0.3–0.4 mm. |
Fruiting pedicels | ascending to divaricate-ascending, straight, 5–14(–17) mm, glabrous. |
divaricate-ascending or ascending, straight, (1.5–)2–6 mm, pubescent, trichomes stalked, stellate, and, sometimes, simple. |
Fruits | elliptic to oblong-elliptic, plane, flattened, 3–10(–14) × 2–3 mm; valves glabrous; ovules 20–28 per ovary; style 0.6–1 mm. |
oblong to lanceolate, plane, slightly flattened, (5–)6–11 × 2–3 mm; valves pubescent, trichomes short-stalked, 2–5-rayed (some rays branched), 0.05–0.3 mm; ovules 20–32 per ovary; style 0.1–1 mm (stigma distinctly wider than style). |
Seeds | oblong, 1.2–1.4 × 0.7–0.8 mm. |
ovoid, 0.8–1.1 × (0.6–)0.7–0.8 mm. |
2n | = 22. |
= 80. |
Draba kassii |
Draba arctica |
|
Phenology | Flowering Apr–Jun. | Flowering Jun–Jul. |
Habitat | Quartzite and granitic outcrops | Clay flats, gravel, beaches, limestone outcrops, talus |
Elevation | 2100-2600 m (6900-8500 ft) | 0-500 m (0-1600 ft) |
Distribution |
UT |
NU; Greenland; Europe (Norway [Svalbard]) |
Discussion | Of conservation concern. Draba kassii is a distinctive species that is known from the Deep Creek Mountains in Juab and Tooele counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
As circumscribed here, Draba arctica consists of two distinct elements often recognized as subspecies (arctica and ostenfeldii; T. W. Böcher 1966); perhaps they are better treated as distinct species (D. arctica and D. ovibovina). Lack of adequate material and inability to examine all of the types in this complex prevent us from doing so. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 315. | FNA vol. 7, p. 291. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. arctica subsp. ostenfeldii, D. arctica var. ostenfeldii, D. cinerea var. arctica, D. ostenfeldii, D. ostenfeldii var. ovibovina, D. ovibovina | |
Name authority | S. L. Welsh: Great Basin Naturalist 46: 264. (1986) | J. Vahl: in G. C. Oeder et al., Fl. Dan. 13(39): plate 5, 2294. (1840) |
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