Boechera consanguinea |
Boechera nevadensis |
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Four Corners rockcress |
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Habit | Biennials or perennials; short-lived; apomictic; caudex present or absent. | Perennials; short- to long-lived; sexual; caudex usually not woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 1.5–5 dm, densely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.2–0.5 mm, glabrous or sparsely pubescent distally. |
usually 2–4 per caudex branch, arising from center of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.6–2 dm, glabrous throughout. |
Basal leaves | blade oblanceolate, 2–10 mm wide, margins usually dentate, sometimes ciliate near petiole base, trichomes (usually spurred), to 0.7 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 4–8-rayed, 0.1–0.4 mm. |
blade oblanceolate, 2–6 mm wide, margins entire, rarely ciliate along petiole, trichomes (simple), 0.5–0.7 mm, surfaces glabrous. |
Cauline leaves | 15–36, sometimes concealing stem proximally; blade auricles 1–3 mm, surfaces of distalmost leaves sparsely pubescent. |
5–9, rarely concealing stem proximally; blade auricles 0.7–2.5 mm, surfaces of distalmost leaves glabrous. |
Racemes | 20–55-flowered, usually unbranched. |
4–12-flowered, usually unbranched. |
Flowers | divaricate-descending at anthesis; sepals pubescent; petals pale lavender, 5–8.5 × 1–2 mm, glabrous; pollen spheroid. |
ascending at anthesis; sepals glabrous; petals lavender, 4–5.5 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed to divaricate-descending, usually curved downward, 8–14 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. |
divaricate-ascending to horizontal, straight, 2.5–8 mm, glabrous. |
Fruits | reflexed to pendent, rarely appressed to rachis, not secund, straight or slightly curved, edges parallel, 4–6 cm × 1–2 mm; valves glabrous; ovules 100–128 per ovary; style 0.05–0.5 mm. |
usually divaricate-ascending, rarely slightly descending, usually secund, straight to slightly curved, 1.9–4 cm × 2–3 mm; valves glabrous; ovules 52–72 per ovary; style 0.05–0.2 mm. |
Seeds | biseriate to sub-biseriate, mature seeds not seen. |
biseriate, 1.1–1.4 × 0.8–1 mm; wing continuous, 0.07–0.15 mm wide. |
Boechera consanguinea |
Boechera nevadensis |
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Phenology | Flowering May. | Flowering Jun. |
Habitat | Rocky slopes and sandy soil in ponderosa pine, pinyon-juniper, and sagebrush communities | Ledges and talus of limestone cliffs |
Elevation | 1900-2500 m (6200-8200 ft) | 3000-3400 m (9800-11200 ft) |
Distribution |
CO; NM; UT
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NV |
Discussion | Morphological evidence suggests that Boechera consanguinea is an apomictic species that arose through hybridization between B. fendleri and B. retrofracta. It is most similar to B. goodrichii, another apomictic hybrid involving B. retrofracta (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Boechera nevadensis usually is treated as a synonym of Arabis pendulina (R. C. Rollins 1993) or B. demissa (N. H. Holmgren 2005b), but is amply distinct from both (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). It is known only from Clark and Nye counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 371. | FNA vol. 7, p. 391. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis consanguinea, Arabis holboellii var. consanguinea | Arabis nevadensis |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 261. (2007) | (Tidestrom) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 73. (2006) |
Web links |