Draba petrophila |
Draba grayana |
|
---|---|---|
Santa Rita Mountain Draba, Santa Rita Mountain whitlowgrass, Santa Rita whitlow grass |
Gray's Draba |
|
Habit | Perennials; (cespitose, long-lived); caudex simple or branched (covered with persistent petioles), not scapose. | Perennials; (densely cespitose); caudex branched (covered with persistent, somewhat thickened, dry petioles); 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, 0.08–0.6 dm, densely to moderately pubescent throughout, trichomes simple and stalked, 2- or 3-rayed, 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; petiolate; petiole ciliate, (trichomes simple, 0.2–1 mm); blade linear to linear-oblanceolate, (0.4–)0.6–1.5(–2) cm × 1–2 mm, margins entire, (pubescent as petiole), surfaces pubescent abaxially with simple and stalked, 2- or 3-rayed trichomes, 0.1–0.4 mm, adaxially glabrate or subapically sparsely pubescent with simple trichomes. |
Cauline leaves | 3–10; sessile; blade ovate to lanceolate or oblong, margins entire or denticulate, surfaces pubescent as basal. |
1–4; sessile; blade linear to linear-oblanceolate, margins entire, surfaces pubescent as basal. |
Racemes | 10–37(–58)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
5–12(–16)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
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, 1.5–2 mm, pubescent, (trichomes simple and short-stalked, 2- or 3-rayed); petals bright yellow, spatulate, 3–4.5 × 1–2 mm, (flared, clawed); anthers ovate, 0.3–0.5 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). |
divaricate-ascending, straight or slightly curved upward, 1.5–6 mm, pubescent as stem. |
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. |
lanceolate to oblong-lanceolate, slightly twisted or plane, flattened, 4–12 × 1.5–3 mm; valves glabrous or pubescent, trichomes simple, 0.07–0.2 mm; ovules 16–20 per ovary; style 0.4–1.2 mm. |
Seeds | ovoid, 1–1.4 × 0.6–0.9 mm. |
ovoid, 1–1.4 × 0.7–1 mm. |
2n | = 24 ± 3. |
|
Draba petrophila |
Draba grayana |
|
Phenology | Flowering Jul–Sep. | Flowering Jul–Aug. |
Habitat | Crevices, ledges of cliffs | Alpine tundra, fellfields, gravelly wet meadows |
Elevation | 1200-2800 m (3900-9200 ft) | 3500-4000 m (11500-13100 ft) |
Distribution |
AZ
|
CO |
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.) |
Of conservation concern. Draba grayana is an apomictic species clearly related to D. exunguiculata, with which it is occasionally sympatric (see discussion of 36. D. exunguiculata for distinguishing features). It is known from Chaffe, Clear Creek, Larimer, Park, and Summit counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 329. | FNA vol. 7, p. 310. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. helleriana var. blumeri, D. helleriana var. petrophila | D. streptocarpa var. grayana, D. alpicola |
Name authority | Greene: Pittonia 4: 17. (1899) | (Rydberg) C. L. Hitchcock: Revis. Drabas W. N. Amer., 29. (1941) |
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