Draba hitchcockii |
Draba murrayi |
|
---|---|---|
lost river Draba |
kathul mountain Draba |
|
Habit | Perennials; (densely cespitose); caudex branched (densely covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose); caudex often branched (covered with persistent leaves or leaf remains, branches sometimes terminating in sterile rosettes); not 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, (0.4–)0.9–2.7(–3.5) dm, pubescent proximally, glabrous distally, trichomes simple, 0.2–1 mm, and often smaller, fewer short-stalked, 2–4-rayed ones. |
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; petiolate; petiole (0–0.7 cm), margin ciliate; blade oblanceolate to obovate, (0.3–)0.6–2.1(–2.8) cm × (1.5–)2.5–5(–9) mm, margins entire or sparsely denticulate, (ciliate, trichomes simple, 0.2–1.1 mm), surfaces pubescent with stalked, cruciform, and 2- or 3-rayed trichomes, (rays sometimes spurred), 0.1–0.6 mm, sometimes mostly simple trichomes adaxially. |
Cauline leaves | 0. |
1–6; sessile; blade ovate or oblong to lanceolate, margins usually entire, rarely sparsely denticulate, surfaces pubescent as basal. |
Racemes | 4–15-flowered, ebracteate, elongated in fruit; rachis not flexuous, hirsute as stem. |
7–25-flowered, ebracteate, 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 ovate, 1.5–2.2 mm, pubescent, (trichomes simple and short-stalked, 2-rayed); petals white, obovate, 4–6 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | ascending, straight, (2–)4–13(–18) mm, hirsute as stem. |
divaricate-ascending, usually straight, rarely curved, (4–)7–18 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. |
linear-lanceolate to narrowly elliptic, plane, flattened, 5–13 × 1.5–2 mm; valves glabrous; ovules 20–30 per ovary; style 0.6–1.5 mm. |
Seeds | oblong, 1.4–1.8 × 0.8–1 mm. |
oblong, 0.9–1.2 × ca. 0.5 mm. |
2n | = 54. |
= 48. |
Draba hitchcockii |
Draba murrayi |
|
Phenology | Flowering May–Jun. | Flowering Jun–Jul. |
Habitat | Limestone outcrops and gravelly soil | Rock outcrops and talus, open forests, dry slopes, alluvial gravels |
Elevation | 1800-2200 m (5900-7200 ft) | 150-900 m (500-3000 ft) |
Distribution |
ID |
AK; YT |
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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 311. | FNA vol. 7, p. 321. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rollins: J. Arnold Arbor. 64: 500. (1983) | G. A. Mulligan: Canad. J. Bot. 57: 1874. (1979) |
Web links |