Boechera villosa |
Boechera cusickii |
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Cusick's rock-cress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | Perennials; long-lived; (often cespitose); sexual; caudex usually woody. |
Stems | 1–3 per caudex branch, arising laterally proximal to sterile shoots near ground surface, ca. 2.5 dm, densely pubescent proximally, trichomes simple and 2-rayed, 0.25–0.7 mm, glabrescent distally. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 1–2.5(–3.8) dm, densely pubescent proximally, trichomes simple, 0.5–1.5 mm, sparsely pubescent or glabrous distally. |
Basal leaves | blade oblanceolate to obovate, 2.5–5 mm wide, margins entire, ciliate along petiole, trichomes (simple), to 1 mm, surfaces densely pubescent, trichomes simple and short-stalked, 2- or 3-rayed, 0.25–0.5 mm. |
blade linear to narrowly oblanceolate, 0.5–2 mm wide, margins entire, ciliate, trichomes (simple), 1–1.7 mm, surfaces moderately pubescent, trichomes simple and long-stalked, 2-rayed, 0.5–1.7 mm. |
Cauline leaves | 4–6, not concealing stem; blade auricles ca. 1 mm, surfaces of distalmost leaves sparsely pubescent. |
10–30, often concealing stem proximally; blade auricles 0–0.5 mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 6–10-flowered, unbranched. |
5–14-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals lavender, 4–5 × 1–1.5 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals white to lavender, 6–10 × 2–3 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | ascending, straight, 6–10 mm, glabrous or sparsely pubescent, trichomes subappressed, branched. |
ascending, straight, 4–15(–20) mm, glabrous or sparsely pubescent, trichomes simple. |
Fruits | divaricate-ascending, not appressed to rachis, not secund, slightly curved, edges parallel, 4–5 cm × ca. 1 mm; valves glabrous; ovules ca. 64 per ovary; style ca. 0.2 mm. |
ascending to divaricate-ascending, not appressed to rachis, not secund, straight or curved, edges parallel, 4–8(–9.5) cm × 2.3–3 mm; valves glabrous; ovules 56–106 per ovary; style 0.1–0.5 mm. |
Seeds | uniseriate, (none mature). |
uniseriate, 1.5–2.5 × 1.5–2 mm; wing continuous, 0.1–0.2 mm wide distally. |
Boechera villosa |
Boechera cusickii |
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Phenology | Flowering May. | Flowering Apr-mid May. |
Habitat | Basalt outcrop in pinyon-juniper woodlands | Basaltic bluffs, rocky slopes, rock crevices, gravelly hillsides, sagebrush hills, outcrops of volcanic rock |
Elevation | ca. 2100 m (ca. 6900 ft) | 600-1800 m (2000-5900 ft) |
Distribution |
NM |
ID; NV; OR; WA
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Discussion | Boechera villosa is known only from the type collection from the Rio Grande Gorge in Taos County. The holotype was originally identified as Arabis (Boechera) perennans but clearly is more closely related to B. pallidifolia (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Peripheral populations of Boechera cusickii in south-central Idaho and northern Nevada have a higher proportion of branched hairs, possibly resulting from hybridization with B. sparsiflora. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 411. | FNA vol. 7, p. 372. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis cusickii | |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 86. (2006) | (S. Watson) Al-Shehbaz: Novon 13: 384. (2003) |
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