Boechera yorkii |
Boechera lincolnensis |
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last chance rock cress |
Lincoln rockcress |
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Habit | Perennials; long-lived; sexual; caudex woody. | Perennials; long-lived; sexual; caudex woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 1–3 dm, densely pubescent proximally, trichomes short-stalked, 4–7-rayed, 0.1–0.5 mm, mixed proximally with simple and short- to long-stalked, 2- or 3-rayed ones, to 1.5 mm, moderately pubescent distally. |
usually 1 per caudex branch, arising from center of leaf tuft, elevated above ground surface on woody base, 2–4.2 dm, densely pubescent proximally, trichomes short-stalked, 3–6-rayed, 0.1–0.5 mm, similarly pubescent distally. |
Basal leaves | blade linear-oblanceolate, 1.5–3 mm wide, margins entire, ciliate proximally, trichomes (simple and 2- or 3-rayed), to 1.5 mm, surfaces moderately pubescent, trichomes short-stalked, 4–7-rayed, 0.3–0.6 mm. |
blade linear or linear-oblanceolate, 1–2 mm wide, margins entire, rarely ciliate near petiole base, trichomes (simple), to 1 mm, surfaces densely pubescent, trichomes short-stalked, 3–8-rayed, 0.1–0.4 mm. |
Cauline leaves | 9–17, concealing stem proximally; blade auricles absent, surfaces of distalmost leaves moderately pubescent. |
10–25, concealing stem proximally; blade auricles absent or, rarely, to 1 mm, surfaces of distalmost leaves densely pubescent. |
Racemes | 8–35-flowered, usually unbranched. |
7–15-flowered, usually unbranched. |
Flowers | pendent at anthesis; sepals pubescent; petals yellowish proximally and brick-red distally or, rarely, one color throughout, 9–10 × 0.8–1 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals pubescent; petals lavender to purple, 10–12 × 2–3 mm, glabrous or sparsely pubescent (occasionally some trichomes abaxially); pollen ellipsoid. |
Fruiting pedicels | reflexed, straight, 1.5–2 mm, pubescent, trichomes appressed, branched. |
divaricate-ascending, straight to slightly curved proximally, recurved distally, 10–20(–25) mm, pubescent, trichomes appressed, branched. |
Fruits | (immature) reflexed, often appressed to rachis, not secund, straight, edges parallel, ca. 4 cm; valves pubescent throughout; style ca. 0.3 mm. |
usually widely pendent to ascending, rarely horizontal, not appressed to rachis, not secund, straight, edges parallel, (3.2–)4–5.5 cm × 2–2.5 mm; valves pubescent throughout; ovules 86–120 per ovary; style 0.1–0.3 mm. |
Seeds | not seen. |
biseriate, 1–1.5 × 0.7–0.9 mm; wing continuous, 0.07–0.12 mm wide. |
2n | = 14. |
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Boechera yorkii |
Boechera lincolnensis |
|
Phenology | Flowering May. | Flowering Apr–May. |
Habitat | Crevices and ledges of calcareous rock outcrops | Rocky slopes and gravelly soil with sagebrush and other shrubs |
Elevation | 2200-2400 m (7200-7900 ft) | 1400-1900 m (4600-6200 ft) |
Distribution |
CA |
CA; NV; UT |
Discussion | Boechera yorkii is immediately recognizable by its yellowish to brick-red petals and extremely short (1.5–2 mm), reflexed fruiting pedicels. It is known only from Last Chance Mountains in Inyo County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Recent studies suggest that Boechera lincolnensis is a distinct species (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 412. | FNA vol. 7, p. 388. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis pulchra var. munciensis, B. pulchra var. munciensis | |
Name authority | S. Boyd: Madroño 51: 387, figs. 1–3. (2004) | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 71. (2006) |
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