Boechera acutina |
Boechera glaucovalvula |
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point rockcress, sharp-pod rock-cress |
bluepod 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, 1.5–6 dm, densely pubescent proximally, trichomes sessile, 2–4-rayed, 0.15–0.4 mm, usually sparsely pubescent distally, rarely glabrous. |
usually 1 per caudex branch, arising from center of rosette near ground surface, (0.6–)1–4.5 dm, densely pubescent proximally, trichomes short-stalked, 4–8-rayed, 0.1–0.4 mm, similarly pubescent distally. |
Basal leaves | blade oblanceolate, 1.5–6 mm wide, margins usually entire, rarely denticulate, ciliate proximally, trichomes (simple), to 0.5 mm, surfaces sparsely to moderately pubescent, trichomes sessile, 3–5 (or 6)-rayed, 0.15–0.35 mm. |
blade linear to linear-oblanceolate, 2–4(–6) mm wide, margins entire, usually ciliate at petiole base, trichomes (simple or spurred), to 1.5 mm, surfaces densely pubescent, trichomes short-stalked, 4–8-rayed, 0.1–0.4 mm. |
Cauline leaves | 2–20(–38), often concealing stem proximally; blade auricles 0.3–2 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
6–10, not concealing stem; blade auricles absent, surfaces of distalmost leaves densely pubescent. |
Racemes | 5–20(–36)-flowered, usually unbranched. |
(5–)10–25-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals white or lavender, 5–7 × 0.9–1.3 mm, glabrous; pollen spheroid. |
divaricate at anthesis; sepals pubescent; petals light purple to lavender, 6–9 × 1.5–2.5 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect to ascending, usually straight, 3–10 mm, pubescent or glabrous, trichomes appressed, branched. |
reflexed, strongly curved at base, 2–10 mm, pubescent, trichomes appressed, branched. |
Fruits | ascending, not appressed to rachis, not secund, straight, edges parallel, 2.5–7.5 cm × 1.2–1.8 mm; valves glabrous; ovules 46–100 per ovary; style 0.3–1 mm. |
strongly reflexed, sometimes appressed to rachis, often secund, straight, edges parallel, (1.8–)2.5–4.5 cm × 5–8 mm; valves glabrous; ovules 24–62 per ovary; style 0.2–0.6 mm. |
Seeds | uniseriate, 1.8–2.2 × 1–1.4 mm; wing continuous, 0.1–0.4 mm wide. |
biseriate, 5–6 × 4–5 mm; wing continuous, 1.8–2.5 mm wide. |
2n | = 14. |
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Boechera acutina |
Boechera glaucovalvula |
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Phenology | Flowering Jun–Jul. | Flowering Mar–Apr. |
Habitat | Gravelly slopes in meadows, open forests | Rocky slopes and gravelly soil, usually under shelter of desert shrubs |
Elevation | 1400-1900 m (4600-6200 ft) | 600-1600 m (2000-5200 ft) |
Distribution |
CA; ID; OR |
CA; NV
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Discussion | Boechera acutina is an apomictic hybrid that clearly contains a genome derived from B. stricta; the other parent remains uncertain. Plants of B. acutina are superficially similar to B. pratincola and are often misidentified as Arabis (Boechera) divaricarpa; the species is easily distinguished from both of those (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Boechera glaucovalvula, a distinctive sexual diploid that has the widest fruits in the genus, is known from Inyo, Mono, Riverside, and San Bernardino counties, California, and Clark and Nye counties, Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 365. | FNA vol. 7, p. 380. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis acutina, Arabis divaricarpa var. interposita, Arabis drummondii var. interposita, Arabis interposita | Arabis glaucovalvula |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 236. (2007) | (M. E. Jones) Al-Shehbaz: Novon 13: 385. (2003) |
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