Boechera dispar |
Boechera porphyrea |
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pinyon rock cress |
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Habit | Perennials; usually long-lived; sexual; caudex often woody. | Perennials; usually long-lived; apomictic; caudex often woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 0.9–3 dm, densely pubescent proximally, trichomes short-stalked, 5–12-rayed, 0.1–0.3 mm, sparsely pubescent to glabrescent distally. |
1 to several per caudex branch, arising from center of rosette or arising laterally proximal to sterile shoots, somewhat elevated on woody base or from ground surface, 2–5(–9) dm, usually glabrous proximally, rarely sparsely pubescent, trichomes simple and short-stalked, 2- or 3-rayed, 0.1–0.5 mm, glabrous distally. |
Basal leaves | blade linear-oblanceolate, 2–5 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5–12(–16)-rayed, 0.1–0.3 mm. |
blade oblanceolate, (3–)5–15 mm wide, margins dentate, ciliate at least along petiole, trichomes to 1 mm, surfaces pubescent, trichomes short-stalked, 2–6-rayed, 0.1–0.5 mm. |
Cauline leaves | 1–5, not concealing stem; blade without auricles, surfaces of distalmost leaves pubescent. |
5–17(–21), sometimes concealing stem proximally; blade auricles 0.5–3.5(–5.5) mm, surfaces of distalmost leaves glabrous. |
Racemes | 4–15(–20)-flowered, unbranched. |
10–30(–70)-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals purple to lavender, 3.5–6 × 1–1.5 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals glabrous; petals lavender, 6.5–8.5 × 1–2.5 mm, glabrous; pollen spheroid. |
Fruiting pedicels | ascending, straight, 4–15(–25) mm, pubescent, trichomes appressed, branched. |
horizontal, gently curved downward, 10–27 mm, glabrous. |
Fruits | divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 4–7.3 cm × 2.7–4 mm; valves glabrous; ovules 44–52 per ovary; style 0.05–0.1 mm. |
widely pendent, not appressed to rachis, not secund, usually curved, edges parallel, 3–7 cm × 1.8–2.5 mm; valves glabrous; ovules 100–160 per ovary; style 0.2–0.5 mm. |
Seeds | uniseriate, 1.9–2.3 mm in diam.; wing continuous, 0.3–0.5 mm wide. |
sub-biseriate, 1.1–1.6 × 0.9–1.1 mm; wing continuous, 0.1–0.2 mm wide. |
Boechera dispar |
Boechera porphyrea |
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Phenology | Flowering Apr–May. | Flowering late Mar-early May. |
Habitat | Rocky slopes and gravelly soil in desert scrub and pinyon-juniper communities | Rocky slopes in evergreen woodlands or desert scrub |
Elevation | 1500-2300 m (4900-7500 ft) | 1200-2100 m (3900-6900 ft) |
Distribution |
CA; NV |
NM; TX |
Discussion | Boechera dispar is a distinctive sexual diploid that is known from Inyo, Mono, and San Bernardino counties, California, and Nye County, Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Morphological evidence suggests that Boechera porphyrea is an apomictic species that arose through hybridization between B. texana and B. perennans (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 374. | FNA vol. 7, p. 398. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis dispar, Arabis juniperina, Arabis nardina, Arabis salubris | Arabis porphyrea |
Name authority | (M. E. Jones) Al-Shehbaz: Novon 13: 384. (2003) | (Wooton & Standley) Windham: Harvard Pap. Bot. 11: 272. (2007) |
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