Draba hitchcockii |
Draba kassii |
|
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lost river Draba |
kass' Draba |
|
Habit | Perennials; (densely cespitose); caudex branched (densely covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; caudex branched (densely covered with persistent petiole remains, branches sometimes terminating in sterile rosettes); scapose. |
Stems | unbranched, (0.1–)0.3–1(–1.3) dm, hirsute throughout, trichomes simple, 0.4–1 mm, and 2–4-rayed, 0.1–0.6 mm. |
unbranched, 0.5–1.8 dm, glabrous. |
Basal leaves | (densely imbricate); rosulate; sessile; blade narrowly oblanceolate to oblong-linear, 0.3–1.2(–1.5) cm × 1–2 mm, margins entire, (ciliate, trichomes simple, 0.3–1.2 mm), surfaces pubescent abaxially with stalked, 2–4-rayed trichomes, 0.08–0.45 mm, (midvein obscure), adaxially glabrous proximally, sparsely pubescent distally with mostly simple trichomes. |
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. |
Cauline leaves | 0. |
0. |
Racemes | 4–15-flowered, ebracteate, elongated in fruit; rachis not flexuous, hirsute as stem. |
3–8(–10)-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, glabrous. |
Flowers | sepals oblong, 2.5–3.5 mm, hirsute, (trichomes simple and stalked, 2–4-rayed); petals white, obovate, 5–6.5 × 2–3.5 mm; anthers ovate, 0.5–0.6 mm. |
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. |
Fruiting pedicels | ascending, straight, (2–)4–13(–18) mm, hirsute as stem. |
ascending to divaricate-ascending, straight, 5–14(–17) mm, glabrous. |
Fruits | ovate to broadly oblong or elliptic, plane, flattened, (3–)4–7(–10) × (2.5–)3.5–5 mm; valves pubescent, trichomes simple and short-stalked, 2(–4)-rayed, 0.06–0.5 mm; ovules 8–12 per ovary; style (0.8–)1–1.7(–2) mm. |
elliptic to oblong-elliptic, plane, flattened, 3–10(–14) × 2–3 mm; valves glabrous; ovules 20–28 per ovary; style 0.6–1 mm. |
Seeds | oblong, 1.4–1.8 × 0.8–1 mm. |
oblong, 1.2–1.4 × 0.7–0.8 mm. |
2n | = 54. |
= 22. |
Draba hitchcockii |
Draba kassii |
|
Phenology | Flowering May–Jun. | Flowering Apr–Jun. |
Habitat | Limestone outcrops and gravelly soil | Quartzite and granitic outcrops |
Elevation | 1800-2200 m (5900-7200 ft) | 2100-2600 m (6900-8500 ft) |
Distribution |
ID |
UT |
Discussion | Draba hitchcockii is known from the Lost River Range in Butte and Custer counties. Based on morphological and chromosomal evidence, M. D. Windham (2004) suggested that it may be an allopolyploid resulting from hybridization between D. oreibata and D. paysonii. Draba hitchcockii is superficially similar to D. jaegeri, a taxon known from the Charleston Mountains of Clark County, Nevada. Both are cespitose perennials with relatively large, white flowers and a chromosome number (2n = 54) otherwise unknown in Draba (Windham). Features distinguishing these two taxa are provided in the discussion of 51. D. jaegeri. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 311. | FNA vol. 7, p. 315. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rollins: J. Arnold Arbor. 64: 500. (1983) | S. L. Welsh: Great Basin Naturalist 46: 264. (1986) |
Web links |