Boechera pygmaea |
Boechera tiehmii |
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Tulare County rock cress |
Tiehm's Rock cress |
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Habit | Perennials; usually long-lived; sexual; caudex woody, (often with persistent, crowded leaf bases). | Perennials; long-lived; sexual; caudex woody (covered by persistent leaf bases). |
Stems | usually 2–5 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.2–0.8 dm, pubescent proximally, trichomes simple and short-stalked, 2- or 3-rayed, to 0.4 mm, glabrescent distally. |
usually 2–5 per caudex branch, arising from margin of rosette near ground surface, 0.8–2(–3) dm, glabrous throughout. |
Basal leaves | blade linear, 0.8–1.5 mm wide, margins entire, ciliate, trichomes (simple and spurred), to 0.8 mm, surfaces moderately pubescent, trichomes short-stalked, 2–4-rayed, 0.05–0.4 mm. |
blade oblanceolate, (2–)3–7 mm wide, margins usually entire, rarely denticulate, ciliate, trichomes (simple and short-stalked) 2- or 3-rayed, 0.2–0.4 mm, surfaces glabrous. |
Cauline leaves | 2–4, not concealing stem; blade auricles absent, surfaces of distalmost leaves pubescent. |
3–5, not concealing stem; blade auricles absent or, rarely, to 0.5 mm, surfaces of distalmost leaves glabrous. |
Racemes | 2–5-flowered, unbranched. |
10–16-flowered, usually unbranched. |
Flowers | erect at anthesis; sepals pubescent; petals white, 3.5–5 × 0.7–1 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals glabrous; petals white to lavender, 4–5 × 1.2–1.7 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect to ascending, straight, 2–7 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. |
ascending, straight, 3–7 mm, glabrous. |
Fruits | erect to ascending, often appressed to rachis, not secund, straight, edges parallel, (1.3–)2–3.3 cm × 4–5 mm; valves glabrous; ovules 8–12 per ovary; style 0.05–0.4 mm. |
ascending, not appressed to rachis, not secund, straight, edges parallel, 1.5–3.7 cm × 1.4–1.7 mm; valves glabrous; ovules 14–22 per ovary; style 0.2–0.6 mm. |
Seeds | uniseriate, 3–5 × 2.5–4.5 mm; wing continuous, 0.8–2 mm wide distally. |
uniseriate, 1.7–2.2 × 1–1.2 mm; wing absent or distal, 0–0.5 mm wide. |
Boechera pygmaea |
Boechera tiehmii |
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Phenology | Flowering May–Jul. | Flowering Jun–Aug. |
Habitat | Barren flats of arkosic gravel | Rock outcrops and gravelly soils in alpine and subalpine habitats |
Elevation | 2400-3200 m (7900-10500 ft) | 3000-3500 m (9800-11500 ft) |
Distribution |
CA |
CA; NV |
Discussion | Of conservation concern. Despite the distinctive morphology of Boechera pygmaea, there is evidence that it is capable of producing fertile hybrids with B. stricta. It is known only from Inyo and Tulare counties in the southern Sierra Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Boechera tiehmii is a sexual species considered by R. C. Rollins (1993) to be related to Arabis (Boechera) davidsonii. It is known only from Mono County, California, and Washoe County, Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 401. | FNA vol. 7, p. 410. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis pygmaea | Arabis tiehmii |
Name authority | (Rollins) Al-Shehbaz: Novon 13: 388. (2003) | (Rollins) Al-Shehbaz: Novon 13: 389. (2003) |
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