Draba oreibata |
Draba jaegeri |
|
---|---|---|
limestone Draba |
Jaeger's Draba |
|
Habit | Perennials; (cespitose); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (densely cespitose); caudex branched (densely covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. |
Stems | unbranched, 0.2–0.9 dm, glabrous throughout. |
unbranched, (0.05–)0.15–0.5(–0.6) dm, hirsute throughout, trichomes simple, 0.1–0.8 mm, and 2–4-rayed, 0.0.5–0.4 mm. |
Basal leaves | rosulate; sessile; blade oblong to narrowly oblanceolate, 0.2–1 cm × 0.6–2(–4) mm, margins entire, (ciliate, trichomes simple, 0.1–0.5 mm, apex obtuse), surfaces glabrous. |
(densely imbricate); rosulate; sessile; blade oblanceolate to ovate, 0.4–1.5 cm × 1.5–3.5 mm, margins entire, (ciliate, trichomes simple, 0.3–1.1 mm), surfaces pubescent abaxially with stalked, (2–)4–6-rayed trichomes, 0.1–5 mm, (midvein obscure), adaxially glabrous proximally, sparsely pubescent distally with mostly simple trichomes. |
Cauline leaves | 0. |
0. |
Racemes | 3–8-flowered, ebracteate, considerably elongated in fruit; rachis slightly flexuous, glabrous. |
3–12(–18)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, hirsute as stem. |
Flowers | sepals oblong, 1.7–2.5 mm, glabrous; petals white, oblanceolate to obovate, 3.5–4.5 × 1.2–2 mm; anthers ovate, 0.3–0.4 mm. |
sepals oblong, 2.5–3 mm, hirsute, (trichomes simple and stalked, 2–4-rayed); petals white, spatulate, 4.5–6 × 1.5–2 mm; anthers oblong, 0.8–1 mm. |
Fruiting pedicels | divaricate-ascending to ascending, straight, 4–13 mm, glabrous. |
ascending, straight, 2–6(–8) mm, hirsute as stem. |
Fruits | oblong to narrowly so, slightly twisted, flattened, 5–9 × 1.5–3 mm; valves glabrous; ovules 8–16 per ovary; style 0.3–0.9(–1.2) mm. |
ovate to elliptic, plane, slightly flattened, 4–8(–11) × 2.5–4.5 mm; valves pubescent, trichomes stalked (2–)4-rayed, 0.05–0.5 mm; ovules 8–16 per ovary; style (1.2–)2–4(–4.5) mm. |
Seeds | oblong, 0.9–1.3 × 0.6–0.8 mm. |
oblong, 1.4–2 × 0.9–1 mm. |
2n | = 32. |
= 54. |
Draba oreibata |
Draba jaegeri |
|
Phenology | Flowering May–Jul. | Flowering Jun–Aug. |
Habitat | Limestone cliffs, talus | Limestone outcrops and gravelly soil |
Elevation | 1800-2700 m (5900-8900 ft) | 2900-3600 m (9500-11800 ft) |
Distribution |
ID |
NV |
Discussion | R. C. Rollins (1993) and N. H. Holmgren (2005b) divided Draba oreibata into two varieties: the Idaho endemic var. oreibata and the Nevada endemic var. serpentina. As indicated by I. A. Al-Shehbaz and M. D. Windham (2007), the two taxa are morphologically distinct, have different chromosome numbers, and are separated by over 480 kilometers. They are treated herein as separate species, and distinguished by characteristics discussed by Al-Shehbaz and Windham. Draba oreibata, in the strict sense, is known from Blaine, Butte, Clark, Custer, and Lemhi counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Draba jaegeri is superficially similar to D. hitchcockii, a narrow endemic of the Lost River Range in central Idaho. Both species are cespitose perennials with relatively large, white flowers, and a chromosome number (2n = 54) otherwise unknown in Draba (M. D. Windham 2004). Draba jaegeri is readily distinguished from D. hitchcockii by having fruits pubescent with (2–)4-rayed trichomes, styles (1.2–)2–4(–4.5) mm, fruiting pedicels 2–6(–8) mm, and spatulate petals 1.5–2 mm wide. By contrast, D. hitchcockii has fruits pubescent with mostly simple and 2-rayed trichomes (with 3- or 4-rayed ones), styles (0.8–)1–1.7(–2) mm, fruiting pedicels (2–)4–13(–18) mm, and obovate petals 2–3.5 mm wide. Draba jaegeri is known only from the Charleston Mountains in Clark County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 325. | FNA vol. 7, p. 314. |
Parent taxa | ||
Sibling taxa | ||
Name authority | J. F. Macbride & Payson: Amer. J. Bot. 4: 257. (1917) | Munz & I. M. Johnston: Bull. Torrey Bot. Club 56: 164. (1929) |
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