Boechera peirsonii |
|
---|---|
Peirson's rockcress, San Bernardino Rock cress |
|
Habit | Perennials; long-lived; (cespitose); apomictic; caudex woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 1–2.5 dm, glabrous or sparsely pubescent proximally, trichomes short-stalked, 2–5-rayed (rarely, some simple), 0.4–0.6 mm, glabrous distally. |
Basal leaves | blade oblanceolate, 2.5–6 mm wide, margins entire, ciliate proximally, trichomes (simple), surfaces densely pubescent, trichomes short-stalked, 4–7-rayed, 0.3–0.5 mm. |
Cauline leaves | 3–12, often concealing stem proximally; blade auricles 0.5–2 mm, surfaces of distalmost leaves usually glabrous, sometimes margins ciliate. |
Racemes | 12–25-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals purple, 5–6 × 1.5–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | ascending to divaricate-descending, straight, 2–6 mm, glabrous. |
Fruits | ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 2–3.7 cm × 2–2.8 mm; valves glabrous; ovules 56–80 per ovary; style 0.1–0.3 mm. |
Seeds | uniseriate, 1–1.5 × 0.8–1 mm; wing distal or continuous, 0.05–0.1 mm wide. |
Boechera peirsonii |
|
Phenology | Flowering Jun–Sep. |
Habitat | Granitic ledges and talus slopes |
Elevation | 2700-3400 m (8900-11200 ft) |
Distribution |
CA |
Discussion | Boechera peirsonii is an apomictic species of unknown origin; although previously treated as a variety of Arabis (B.) breweri, it is quite distinct from that taxon (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). All known collections come from the San Bernardino Mountains of southern California, ca. 200 km distant from the nearest populations of B. breweri. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. |
Parent taxa | |
Sibling taxa | |
Synonyms | Arabis breweri var. pecuniaria |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 270. (2007) |
Web links |
|