Draba asprella var. asprella |
Draba asprella |
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rough Draba |
rough Draba, rough whitlowgrass |
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Habit | Perennials; (cespitose); caudex branched (with some persistent leaf bases); scapose. | |||||
Stems | unbranched, (0.4–)0.6–1.5(–2.7) dm, pubescent throughout, trichomes simple, 0.5–1.5 mm, and 2–4-rayed ones, 0.05–0.3 mm, (sometimes 2–4-rayed ones distally). |
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Basal leaves | rosulate; subsessile or shortly petiolate; petiole ciliate throughout; blade oblanceolate to spatulate or obovate, (0.6–)0.8–4.5(–6) cm × 2–12(–16) mm, margins usually entire, rarely obscurely dentate, (not ciliate), surfaces abaxially pubescent with stalked, (2–)4-rayed trichomes, 0.2–1 mm, adaxially with stalked, 2–4-rayed trichomes, 0.3–0.8 mm, and simple ones, 0.5–1.9 mm. |
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Cauline leaves | 0. |
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Racemes | (15–)30–75-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent, trichomes 2–4-rayed, sometimes with simple ones. |
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Flowers | sepals broadly ovate, 1.8–3.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed); petals pale yellow, oblanceolate, 4–7 × 1.5–2.5 mm; anthers ovate to oblong, 0.4–0.7 mm. |
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Fruiting pedicels | horizontal to divaricate-ascending, straight, 3–11(–16) mm, pubescent, trichomes 2–4-rayed, sometimes with simple ones. |
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Fruit(s) | valves hirsute, trichomes simple and unequally 2-rayed, (0.2–)0.3–1 mm. |
ovoid-ellipsoid to oblong, plane, inflated basally, 3–8 × 1.8–3.5 mm; valves hirsute, trichomes simple and spurred, (0.2–)0.3–1 mm, or puberulent, trichomes short-stalked, 2–4-rayed, 0.1–0.2 mm; ovules 8–12(–18) per ovary; style 0.6–2(–2.5) mm. |
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Seeds | oblong, 0.9–1.2 × 0.6–0.8 mm. |
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2n | = 30. |
= 30. |
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Draba asprella var. asprella |
Draba asprella |
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Phenology | Flowering Mar–May. | |||||
Habitat | Rocky igneous soil in pine-oak woodlands | |||||
Elevation | 1500-2500 m (4900-8200 ft) | |||||
Distribution |
AZ |
AZ
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Discussion | Variety asprella is known only from Coconino and Yavapai counties in central Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). Both R. C. Rollins (1993) and N. H. Holmgren (2005b) indicated that the chromosome number of Draba asprella is 2n = 32, but repeated counts by one of us (M. D. Windham 2000, unpubl.) show that the species consistently has 2n = 30. Rollins divided D. asprella into four varieties encompassing tremendous variation in trichome morphology. One of these (var. zionensis) is more closely related to D. sobolifera (Windham and L. Allphin, unpubl.) and is treated herein at species rank. Within D. asprella, in the strict sense, we recognize two varieties separated primarily by the type of trichomes found on the fruits. The distinctions are not absolute and there appear to be forms connecting the two, especially in Coconino County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 7, p. 293. | FNA vol. 7, p. 293. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | unknown | Greene: Bull. Torrey Bot. Club 10: 125. (1883) | ||||
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