Boechera perstellata |
Boechera constancei |
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Constance's Rock cress |
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Habit | Perennials; usually short-lived; sexual; caudex not woody. | Perennials; long-lived; sexual; caudex woody. |
Stems | 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. |
usually 1 per caudex branch, arising from center of rosette, elevated above ground surface on woody base, 1.2–3 dm, glabrous throughout. |
Basal leaves | 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. |
blade narrowly oblanceolate, 1.5–4 mm wide, margins entire, ciliate, trichomes (simple, mixed with fewer stalked, 2-rayed), 0.3–0.8 mm, surfaces glabrous. |
Cauline leaves | 6–25, concealing stem proximally; blade auricles 1–6 mm, surfaces of distalmost leaves pubescent. |
6–12, not concealing stem; blade auricles absent, surfaces of distalmost leaves glabrous. |
Racemes | 10–40-flowered, usually unbranched. |
5–15-flowered, unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals purplish, 3–4 × 0.7–1 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals glabrous; petals creamy white, 6–8 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | usually horizontal, usually straight, rarely slightly curved, 5–15 mm, pubescent, trichomes spreading, simple. |
arched, strongly recurved proximally, 4–12 mm, glabrous. |
Fruits | 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. |
pendent, not appressed to rachis, usually secund, straight or slightly curved, edges often somewhat undulate (not parallel), 4–7.5 cm × 3–3.5 mm; valves glabrous; ovules 18–28 per ovary; style 2.5–5 mm. |
Seeds | uniseriate, 0.8–1.1 × 0.6–0.8 mm, not winged. |
uniseriate, 3–4 × 2.5–3 mm; wing continuous, 0.5–1 mm wide. |
2n | = 14. |
= 14. |
Boechera perstellata |
Boechera constancei |
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Phenology | Flowering Apr–May. | Flowering May. |
Habitat | Calcareous bluffs and wooded hillsides | Steep ridges, serpentine slopes |
Elevation | 200-400 m (700-1300 ft) | 1200-1900 m (3900-6200 ft) |
Distribution |
KY; TN |
CA |
Discussion | 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.) |
Boechera constancei was originally treated as a variety of Arabis (Boechera) suffrutescens; it is easily separated from that species by its non-auriculate cauline leaf blades, longer (6–8 versus 4.5–6 mm) petals that are creamy white (versus purple or rose-tipped), much longer style (2.5–5 versus 0.4–1.2 mm), and exerted anthers. This distinctive sexual diploid is thus far known only from the west slope of the Sierra Nevada in Plumas County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 396. | FNA vol. 7, p. 371. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis perstellata, Arabis perstellata var. ampla | Arabis constancei, Arabis suffrutescens var. perstylosa |
Name authority | (E. L. Braun) Al-Shehbaz: Novon 13: 388. (2003) | (Rollins) Al-Shehbaz: Novon 13: 384. (2003) |
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