Draba petrophila |
Draba abajoensis |
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Santa Rita Mountain Draba, Santa Rita Mountain whitlowgrass, Santa Rita whitlow grass |
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Habit | Perennials; (cespitose, long-lived); caudex simple or branched (covered with persistent petioles), not scapose. | Perennials; caudex simple or branched, (sometimes with persistent leaf bases); not scapose. |
Stems | usually unbranched, rarely branched, 0.3–1.9(–2.8) dm, moderately to densely hirsute throughout, trichomes simple, 0.2–1.3 mm, with short-stalked to subsessile, cruciform, 0.02–0.4 mm, and 2-rayed ones, 0.3–0.9 mm. |
unbranched, (0.6–)1–2.5(–3.5) dm, pubescent proximally, usually glabrous distally, rarely sparsely pubescent, trichomes simple, 0.1–0.5 mm, often with stalked, 2(–4)-rayed ones. |
Basal leaves | rosulate; petiolate; petiole ciliate, (trichomes simple, 0.4–1.5 mm); blade oblanceolate, 1–5(–6) cm × 2–5(–10) mm, margins usually entire, rarely denticulate, surfaces pubescent, abaxially with stalked, cruciform trichomes, 0.07–0.5 mm, adaxially often similar, sometimes with fewer, simple and 2-rayed trichomes, 0.4–1.3 mm. |
rosulate; petiolate; petiole (0.2–1(–2) cm), proximal margin ciliate, (trichomes simple, 0.2–0.7 mm); blade oblanceolate to spatulate, (0.6–)1–3.5(–4.3) cm × (2–)4–10(–14) mm, margins entire or dentate, surfaces pubescent with short-stalked, (2–)4-rayed trichomes, 0.05–0.35 mm, sometimes adaxially with simple ones. |
Cauline leaves | 3–10; sessile; blade ovate to lanceolate or oblong, margins entire or denticulate, surfaces pubescent as basal. |
(3–)5–9(–11); sessile; blade broadly ovate to lanceolate or oblong, margins entire or dentate, surfaces pubescent as basal or adaxially also with mostly simple trichomes. |
Racemes | 10–37(–58)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
(11–)15–32(–47)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent, trichomes simple and short-stalked, 2–4-rayed. |
Flowers | sepals oblong, 2–3.5 mm, pubescent, (trichomes simple and 2-rayed); petals yellow, oblanceolate, 3.5–6 × 1.2–1.8 mm; anthers oblong, 0.8–1 mm. |
sepals ovate-oblong, 2.2–3.5 mm, subapically sparsely pubescent, (trichomes simple, short-stalked, and 2-rayed); petals yellow, oblanceolate, 4–6 × 1.5–2 mm; anthers oblong, 0.6–1 mm. |
Fruiting pedicels | divaricate-ascending, straight, 4–10 mm, pubescent throughout, trichomes simple (0.1–0.5 mm) and subsessile, 2–4-rayed, (0.03–0.2 mm). |
horizontal to divaricate-ascending, straight or curved, (5–)7–18(–23) mm, glabrous or sparsely pubescent abaxially, trichomes simple and 2-rayed. |
Fruits | lanceolate to elliptic, often strongly twisted, flattened, 5–11 × 2–3 mm; valves puberulent at least along margin, trichomes simple, antrorse, 0.03–0.15 mm; ovules 14–24 per ovary; style 0.8–1.8(–2.5) mm. |
elliptic to elliptic-lanceolate, plane, flattened, 5–9(–12) × 2–3 mm; valves glabrous; ovules 10–18 per ovary; style (0.8–)1.4–2.7(–3.6) mm. |
Seeds | ovoid, 1–1.4 × 0.6–0.9 mm. |
ovoid, 1–1.2 × 0.7–0.8 mm. |
2n | = 20. |
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Draba petrophila |
Draba abajoensis |
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Phenology | Flowering Jul–Sep. | Flowering May–Aug. |
Habitat | Crevices, ledges of cliffs | Spruce, fir, or pine forests, subalpine meadows |
Elevation | 1200-2800 m (3900-9200 ft) | 1900-3800 m (6200-12500 ft) |
Distribution |
AZ
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AZ; NM; UT |
Discussion | Draba petrophila is often broadly circumscribed to include the taxon herein called D. viridis. For a discussion of the differences between these species and the closely related D. helleriana, see I. A. Al-Shehbaz and M. D. Windham (2007). Draba petrophila, in the strict sense, is known only from Cochise, Pima, and Santa Cruz counties in southeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Plants of Draba abajoensis were treated by C. L. Hitchcock (1941), R. C. Rollins (1993), and N. H. Holmgren (2005b) as D. spectabilis. The differences between these taxa in chromosome number and trichome morphology strongly support their recognition as separate species (I. A. Al-Shehbaz and M. D. Windham 2007). Draba abajoensis has been collected from the Chuska and Lukachukai mountains in Apache County, Arizona, Chuska Mountains in San Juan County, New Mexico, and Abajo and La Sal mountains in San Juan and Grand counties, Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 329. | FNA vol. 7, p. 288. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. helleriana var. blumeri, D. helleriana var. petrophila | D. spectabilis var. glabrescens |
Name authority | Greene: Pittonia 4: 17. (1899) | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 416. (2007) |
Web links |