Boechera lasiocarpa |
Boechera consanguinea |
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Four Corners rockcress |
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Habit | Perennials; long-lived; sexual; caudex often woody. | Biennials or perennials; short-lived; apomictic; caudex present or absent. |
Stems | 1 or few per caudex branch, arising from center or margin of rosette, somewhat elevated on woody base or near ground surface, (0.7–)2–3.5 dm, densely pubescent proximally, trichomes short-stalked, 4–8-rayed, 0.05–0.15 mm, moderately to sparsely pubescent distally. |
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. |
Basal leaves | blade narrowly oblanceolate, 2–5 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 4–8-rayed, 0.05–0.15 mm. |
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. |
Cauline leaves | 4–10, often concealing stem proximally; blade auricles absent, surfaces of distalmost leaves sparsely to moderately pubescent. |
15–36, sometimes concealing stem proximally; blade auricles 1–3 mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 5–12-flowered, usually unbranched. |
20–55-flowered, usually unbranched. |
Flowers | divaricate at anthesis; sepals pubescent; petals purple to lavender, 6–10 × 1.5–2.5 mm, glabrous; pollen ellipsoid. |
divaricate-descending at anthesis; sepals pubescent; petals pale lavender, 5–8.5 × 1–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | descending, recurved, 4–14 mm, pubescent, trichomes appressed, branched. |
reflexed to divaricate-descending, usually curved downward, 8–14 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. |
Fruits | pendent, usually not appressed to rachis, rarely secund, straight or curved, 2–5 cm × 1.7–2.2 mm; valves glabrous or pubescent throughout; ovules 26–36 per ovary; style 0.2–0.9 mm. |
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. |
Seeds | uniseriate, 1.5–2 × 1–1.5 mm; wing distal or continuous, 0.1–0.2 mm wide. |
biseriate to sub-biseriate, mature seeds not seen. |
Boechera lasiocarpa |
Boechera consanguinea |
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Phenology | Flowering May–Jun. | Flowering May. |
Habitat | Rocky ridges and slopes with dwarf sagebrush | Rocky slopes and sandy soil in ponderosa pine, pinyon-juniper, and sagebrush communities |
Elevation | 1800-2800 m (5900-9200 ft) | 1900-2500 m (6200-8200 ft) |
Distribution |
UT |
CO; NM; UT
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Discussion | Boechera lasiocarpa is a sexual species that appears to be restricted to the Bear River Mountains and northern Wasatch Range in north-central Utah. Reports of Arabis (Boechera) lasiocarpa from central Idaho (e.g., R. C. Rollins 1993; N. H. Holmgren 2005b) represent B. rollinsiorum (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 387. | FNA vol. 7, p. 371. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis lasiocarpa | Arabis consanguinea, Arabis holboellii var. consanguinea |
Name authority | (Rollins) Dorn: Brittonia 55: 3. (2003) | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 261. (2007) |
Web links |