Boechera yorkii |
Boechera perstellata |
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last chance rock cress |
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Habit | Perennials; long-lived; sexual; caudex woody. | Perennials; usually short-lived; sexual; caudex not 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 2–5 per plant, arising from margin of rosette near ground surface, (1–)2–8 dm, densely pubescent proximally, trichomes short-stalked, 3- or 4-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 obovate to oblanceolate, (5–)10–45 mm wide, margins usually coarsely dentate, rarely sinuate, ciliate on petiole base, surfaces moderately pubescent, trichomes short-stalked, 3- or 4(–6)-rayed, 0.1–0.5 mm. |
Cauline leaves | 9–17, concealing stem proximally; blade auricles absent, surfaces of distalmost leaves moderately pubescent. |
6–25, concealing stem proximally; blade auricles 1–6 mm, surfaces of distalmost leaves pubescent. |
Racemes | 8–35-flowered, usually unbranched. |
10–40-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. |
ascending at anthesis; sepals pubescent; petals purplish, 3–4 × 0.7–1 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed, straight, 1.5–2 mm, pubescent, trichomes appressed, branched. |
usually horizontal, usually straight, rarely slightly curved, 5–15 mm, pubescent, trichomes spreading, simple. |
Fruits | (immature) reflexed, often appressed to rachis, not secund, straight, edges parallel, ca. 4 cm; valves pubescent throughout; style ca. 0.3 mm. |
usually horizontal, not appressed to rachis, not secund, straight, edges parallel, (1.5–)2–3.3 cm × 0.8–1 mm; valves sparsely pubescent throughout; ovules 12–20 per ovary; style 0.4–0.8 mm. |
Seeds | not seen. |
uniseriate, 0.8–1.1 × 0.6–0.8 mm, not winged. |
2n | = 14. |
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Boechera yorkii |
Boechera perstellata |
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Phenology | Flowering May. | Flowering Apr–May. |
Habitat | Crevices and ledges of calcareous rock outcrops | Calcareous bluffs and wooded hillsides |
Elevation | 2200-2400 m (7200-7900 ft) | 200-400 m (700-1300 ft) |
Distribution |
CA |
KY; TN |
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.) |
Of conservation concern. Boechera perstellata is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 412. | FNA vol. 7, p. 396. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis perstellata, Arabis perstellata var. ampla | |
Name authority | S. Boyd: Madroño 51: 387, figs. 1–3. (2004) | (E. L. Braun) Al-Shehbaz: Novon 13: 388. (2003) |
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