Draba petrophila |
Draba streptocarpa |
|
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Santa Rita Mountain Draba, Santa Rita Mountain whitlowgrass, Santa Rita whitlow grass |
pretty Draba, pretty whitlowgrass, twisted pod Draba |
|
Habit | Perennials; (cespitose, long-lived); caudex simple or branched (covered with persistent petioles), not scapose. | Perennials; (tufted); caudex simple or branched (covered with persistent leaf remains); 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. |
usually unbranched, (0.2–)0.4–2.5 dm, hirsute proximally, sparsely pubescent or glabrous distally or throughout, trichomes simple, 0.4–2.2 mm, often with stalked, 2(–4)-rayed ones, 0.2–1 mm. |
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; blade oblong-oblanceolate to linear-oblanceolate, 0.5–3.8 cm × 1.5–6 mm, margins entire, (ciliate, trichomes setiform, simple, 0.6–2.8 mm), surfaces strigose to hirsute abaxially with long-stalked, 2(–4)-rayed trichomes, 0.4–1.4 mm, usually with simple ones, strigose adaxially with simple trichomes, 0.7–2.4 mm. |
Cauline leaves | 3–10; sessile; blade ovate to lanceolate or oblong, margins entire or denticulate, surfaces pubescent as basal. |
2–15; sessile; blade oblong to lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | 10–37(–58)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
9–62-flowered, ebracteate or proximalmost 1–3 flowers bracteate, elongated in fruit; rachis not flexuous, sparsely pubescent as stem or glabrous. |
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 oblong, 2.5–3.5 mm, usually pubescent, rarely glabrous, (trichomes simple, sometimes with stalked, 2-rayed ones); petals yellow, oblanceolate to spatulate, (4–)5–7.5 × 1–2(–2.5) mm; anthers ovate, 0.5–0.7 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). |
ascending, slightly curved or straight, 4–12 mm, glabrous or pubescent abaxially, trichomes simple (0.4–1.6 mm). |
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. |
ovate to linear-lanceolate, usually strongly twisted (to 3 turns), rarely plane, flattened, 5–16 × 2–3 mm; valves puberulent along margin, trichomes simple, 0.05–0.3 mm; ovules 20–34 per ovary; style (0.8–) 1–2(–2.5) mm. |
Seeds | ovoid, 1–1.4 × 0.6–0.9 mm. |
ovoid, 0.9–1.2 × 0.6–0.7 mm. |
2n | = 20, 40. |
|
Draba petrophila |
Draba streptocarpa |
|
Phenology | Flowering Jul–Sep. | Flowering May–Jul. |
Habitat | Crevices, ledges of cliffs | Rock outcrops, hillsides and meadows in open mixed conifer forests, aspen groves, and alpine tundra communities |
Elevation | 1200-2800 m (3900-9200 ft) | 2400-4000 m (7900-13100 ft) |
Distribution |
AZ
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CO; NM; WY
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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.) |
Draba streptocarpa is easily recognized by its strongly twisted fruits and broad-based, simple cilia on the basal leaves. It is found primarily in Colorado, but has also been collected in Larimer County, Wyoming, and Mora, San Miguel, and Taos counties, New Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 329. | FNA vol. 7, p. 342. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. helleriana var. blumeri, D. helleriana var. petrophila | D. streptocarpa var. tonsa, D. tonsa |
Name authority | Greene: Pittonia 4: 17. (1899) | A. Gray: Amer. J. Sci. Arts, ser. 2, 33: 242. (1862) |
Web links |