Draba santaquinensis |
Draba hitchcockii |
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lost river Draba |
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Habit | Biennials or perennials; (short-lived); caudex simple (poorly developed, without persistent leaf bases); not scapose. | Perennials; (densely cespitose); caudex branched (densely covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. |
Stems | usually branched, 1.1–3.4 dm, hirsute proximally, trichomes mostly simple and 2-rayed, 0.2–1.5 mm, pubescent distally, trichomes mostly 2- or 3-rayed, 0.2–1 mm. |
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. |
Basal leaves | rosulate; petiole (obscure), ciliate, (trichomes simple and 2-rayed); blade obovate to oblanceolate, 1.6–2.5 cm × 5–10 mm, margins usually entire, rarely denticulate, surfaces pubescent, abaxially with stalked, mostly cruciform trichomes, 0.5–1 mm, adaxially with simple and stalked, 2–4-rayed ones. |
(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. |
Cauline leaves | usually 1–5; sessile or subsessile; blade oblanceolate to oblong, margins often denticulate, (ciliate proximally, with 2- or 3-rayed trichomes). |
0. |
Racemes | 9–25-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent, trichomes 2- or 3-rayed. |
4–15-flowered, ebracteate, elongated in fruit; rachis not flexuous, hirsute as stem. |
Flowers | sepals oblong-obovate, 2–3.5 mm, pubescent, (trichomes short- to long-stalked, 2–4-rayed, 0.2–0.8 mm); petals yellow (often fading whitish), oblanceolate, 3–5 × 1–1.5 mm; anthers ovate, 0.4–0.5 mm. |
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. |
Fruiting pedicels | horizontal to divaricate-ascending, usually straight, rarely curved upward, 7–10 mm, pubescent, trichomes 2- or 3-rayed. |
ascending, straight, (2–)4–13(–18) mm, hirsute as stem. |
Fruits | narrowly elliptic to slightly falcate, plane, flattened, (7–)10–16 × (2–)2.5–3.7 mm; valves pubescent, trichomes short-stalked, 2–4-rayed, 0.2–0.5 mm; ovules 14–22 per ovary; style 0.9–1.2 mm. |
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. |
Seeds | oblong, 1.1–1.5 × 0.7–0.9 mm. |
oblong, 1.4–1.8 × 0.8–1 mm. |
2n | = 20. |
= 54. |
Draba santaquinensis |
Draba hitchcockii |
|
Phenology | Flowering late Apr-early Jun. | Flowering May–Jun. |
Habitat | Limestone outcrops and rocky slopes in mixed conifer communities | Limestone outcrops and gravelly soil |
Elevation | 1800-2400 m (5900-7900 ft) | 1800-2200 m (5900-7200 ft) |
Distribution |
UT |
ID |
Discussion | Although Draba santaquinensis was included within D. brachystylis by previous authors, I. A. Al-Shehbaz and M. D. Windham (2007) have shown that it is distinct both morphologically and chromosomally. It is currently known only from Utah County (American Fork, Provo, and Santaquin canyons) in north-central Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 334. | FNA vol. 7, p. 311. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Windham & Allphin: Harvard Pap. Bot. 12: 410. (2007) | Rollins: J. Arnold Arbor. 64: 500. (1983) |
Web links |