Boechera villosa |
Boechera rigidissima |
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Trinity Mountain rockcress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | Perennials; long-lived; apomictic; caudex woody. |
Stems | 1–3 per caudex branch, arising laterally proximal to sterile shoots near ground surface, ca. 2.5 dm, densely pubescent proximally, trichomes simple and 2-rayed, 0.25–0.7 mm, glabrescent distally. |
usually 1 per caudex branch, arising from center of rosette, slightly elevated on woody base or from near ground surface, 2–6 dm, pubescent proximally, trichomes usually subsessile, 2- or 3-rayed, rarely simple, 0.25–0.4 mm, glabrous distally. |
Basal leaves | blade oblanceolate to obovate, 2.5–5 mm wide, margins entire, ciliate along petiole, trichomes (simple), to 1 mm, surfaces densely pubescent, trichomes simple and short-stalked, 2- or 3-rayed, 0.25–0.5 mm. |
blade oblanceolate, 2–6 mm wide, margins entire, ciliate proximally, trichomes to 0.7 mm, surfaces sparsely pubescent, trichomes subsessile to short-stalked, 2–5-rayed, 0.1–0.4 mm. |
Cauline leaves | 4–6, not concealing stem; blade auricles ca. 1 mm, surfaces of distalmost leaves sparsely pubescent. |
5–10, rarely concealing stem proximally; blade auricles 0.5–2 mm, surfaces of distalmost leaves glabrous. |
Racemes | 6–10-flowered, unbranched. |
5–16-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals lavender, 4–5 × 1–1.5 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals glabrous; petals purple, 6–8 × 1.5–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | ascending, straight, 6–10 mm, glabrous or sparsely pubescent, trichomes subappressed, branched. |
divaricate-ascending, straight, 4–10 mm, glabrous. |
Fruits | divaricate-ascending, not appressed to rachis, not secund, slightly curved, edges parallel, 4–5 cm × ca. 1 mm; valves glabrous; ovules ca. 64 per ovary; style ca. 0.2 mm. |
divaricate-ascending, not appressed to rachis, not secund, straight, edges somewhat undulate (not parallel), 4–6.5(–7.6) cm × 2.5–3.5 mm; valves glabrous; ovules 24–54 per ovary; style 0.2–0.8 mm. |
Seeds | uniseriate, (none mature). |
uniseriate, 2.5–3.2 × 1.8–2.5 mm; wing distal, 0.3–1 mm wide. |
Boechera villosa |
Boechera rigidissima |
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Phenology | Flowering May. | Flowering Jul–Aug. |
Habitat | Basalt outcrop in pinyon-juniper woodlands | Rocky places in open conifer forests |
Elevation | ca. 2100 m (ca. 6900 ft) | 1800-2000 m (5900-6600 ft) |
Distribution |
NM |
CA; NV |
Discussion | Boechera villosa is known only from the type collection from the Rio Grande Gorge in Taos County. The holotype was originally identified as Arabis (Boechera) perennans but clearly is more closely related to B. pallidifolia (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Plants assigned to Boechera rigidissima appear to represent a series of apomictic hybrids, possibly involving B. stricta and B. suffrutescens. The two varieties recognized by Rollins are well isolated geographically (in Trinity County, California, and Washoe County, Nevada, respectively) and show enough morphological divergence to suggest that they represent distinct origins, if not different combinations of parental genomes. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 411. | FNA vol. 7, p. 403. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis rigidissima, Arabis rigidissima var. demota | |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 86. (2006) | (Rollins) Al-Shehbaz: Novon 13: 389. (2003) |
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