Boechera villosa |
Boechera cobrensis |
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cobre rock-cress, Masonic rock-cress, sagebrush rockcress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | Perennials; long-lived; (often cespitose); sexual; caudex somewhat woody (usually without persistent leaf bases). |
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–)2.5–6 dm, densely pubescent proximally, trichomes short-stalked, 4–10-rayed, 0.1–0.2 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, 1–4 mm wide, margins entire, ciliate near petiole base, trichomes (simple), to 0.6 mm, surfaces densely pubescent, trichomes short-stalked, 4–10-rayed, 0.1–0.2 mm. |
Cauline leaves | 4–6, not concealing stem; blade auricles ca. 1 mm, surfaces of distalmost leaves sparsely pubescent. |
5–10, not concealing stem; blade auricles 1–1.5 mm, surfaces of distalmost leaves usually sparsely pubescent. |
Racemes | 6–10-flowered, unbranched. |
10–25-flowered, often sparingly branched. |
Flowers | ascending at anthesis; sepals pubescent; petals lavender, 4–5 × 1–1.5 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals pubescent; petals white to lavender, 3.5–6 × 0.7–1 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | ascending, straight, 6–10 mm, glabrous or sparsely pubescent, trichomes subappressed, branched. |
divaricate-ascending to horizontal, often straight proximally, usually strongly recurved or reflexed distally, 4–17 mm, usually pubescent, rarely glabrous, trichomes appressed, branched. |
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. |
pendent, not appressed to rachis, not secund, straight or slightly curved, edges parallel, 2.5–5.5 cm × 1.7–2.5 mm; valves glabrous; ovules 34–64 per ovary; style 0.05–0.2 mm. |
Seeds | uniseriate, (none mature). |
uniseriate, 1.4–1.8 × 1–1.2 mm; wing continuous, 0.25–0.5 mm wide. |
2n | = 14. |
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Boechera villosa |
Boechera cobrensis |
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Phenology | Flowering May. | Flowering May–Jun. |
Habitat | Basalt outcrop in pinyon-juniper woodlands | Sandy soil, usually under shelter of shrubs in semi-desert communities |
Elevation | ca. 2100 m (ca. 6900 ft) | 1200-2800 m (3900-9200 ft) |
Distribution |
NM |
CA; ID; NV; OR; WY
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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.) |
Boechera cobrensis is a sexual diploid commonly found on stabilized sand dunes. The related B. lignifera often is found in similar habitats, and the two species can be difficult to distinguish where their ranges overlap in Idaho and Wyoming. It is possible that B. cobrensis was involved in the origin of some apomictic populations currently assigned to B. lignifera. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 411. | FNA vol. 7, p. 370. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis cobrensis | |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 86. (2006) | (M. E. Jones) Dorn: Vasc. Pl. Wyoming ed. 3, 375. (2001) |
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