Boechera dispar |
Boechera pendulina |
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pinyon rock cress |
nodding rock cress, rabbit-ear rockcress |
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Habit | Perennials; usually long-lived; sexual; caudex often woody. | Perennials; short- to long-lived; sexual or apomictic; caudex sometimes 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. |
usually 2–6 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.6–3(–3.7) dm, sparsely to densely pubescent proximally, trichomes simple, 0.3–0.8 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 to obovate, 1.5–6 mm wide, margins usually entire, rarely dentate, ciliate throughout, trichomes (usually simple), 0.4–1 mm, surfaces pubescent, trichomes simple and short- and long-stalked, 2-rayed, 0.3–0.8 mm. |
Cauline leaves | 1–5, not concealing stem; blade without auricles, surfaces of distalmost leaves pubescent. |
2–10(–13), not concealing stem; blade auricles absent or, rarely, to 0.7 mm, surfaces of distalmost leaves glabrous or margins sparsely ciliate. |
Racemes | 4–15(–20)-flowered, unbranched. |
4–14-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals purple to lavender, 3.5–6 × 1–1.5 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals usually sparsely pubescent, rarely glabrous; petals whitish to pale lavender, 4–6 × 1–1.5 mm, glabrous; pollen ellipsoid or spheroid. |
Fruiting pedicels | ascending, straight, 4–15(–25) mm, pubescent, trichomes appressed, branched. |
divaricate-ascending to horizontal, curved or angled downward, 3–7(–10) mm, usually glabrous, rarely with some simple trichomes. |
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, curved to nearly straight, edges parallel, 2.2–4 cm × 1.2–2.1 mm; valves glabrous; ovules 40–70(–90) per ovary; style 0.1–0.3(–0.5) mm. |
Seeds | uniseriate, 1.9–2.3 mm in diam.; wing continuous, 0.3–0.5 mm wide. |
biseriate, 0.9–1.2 × 0.6–0.9 mm, usually not winged. |
2n | = 14, 21. |
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Boechera dispar |
Boechera pendulina |
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Phenology | Flowering Apr–May. | Flowering Apr–Jun. |
Habitat | Rocky slopes and gravelly soil in desert scrub and pinyon-juniper communities | Rock outcrops, open gravelly flats and hillsides in sagebrush, pinyon-juniper, mountain mahogany, open conifer forests |
Elevation | 1500-2300 m (4900-7500 ft) | 1600-3100 m (5200-10200 ft) |
Distribution |
CA; NV |
AZ; CA; CO; NV; UT; WY
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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.) |
Although included in Arabis (Boechera) demissa by some authors (e.g., S. L. Welsh et al. 2003; N. H. Holmgren 2005b), B. pendulina is readily distinguished from that species (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). Typical collections are sexual diploids, whereas the type of var. russeola is a triploid apomict; further study is needed to determine if the two are conspecific. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 374. | FNA vol. 7, p. 395. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis dispar, Arabis juniperina, Arabis nardina, Arabis salubris | Arabis pendulina, Arabis demissa var. russeola, Arabis diehlii, Arabis pendulina var. russeola, Arabis setulosa, B. demissa var. pendulina, B. demissa var. russeola, B. pendulina var. russeola |
Name authority | (M. E. Jones) Al-Shehbaz: Novon 13: 384. (2003) | (Greene) W. A. Weber: Phytologia 51: 370. (1982) |
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