Boechera pendulina
Phytologia 51: 370. 1982.
Perennials; short to long-lived; sexual or apomictic; caudex sometimes woody. Stems usually 2–6 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.6–3 (–3.7) dm, sparsely to densely pubescent proximally, trichomes simple, 0.3–0.8 mm, glabrous distally. Basal leaves: blade oblanceolate to obovate, 1.5–6 mm wide, margins usually entire, rarely dentate, ciliate throughout, trichomes (usually simple), 0.4–1 mm, surfaces pubescent, trichomes simple and short and long-stalked, 2-rayed, 0.3–0.8 mm. Cauline leaves: 2–10 (–13), not concealing stem; blade auricles absent or, rarely, to 0.7 mm, surfaces of distalmost leaves glabrous or margins sparsely ciliate. Racemes 4–14-flowered, usually unbranched. Fruiting pedicels divaricate-ascending to horizontal, curved or angled downward, 3–7 (–10) mm, usually glabrous, rarely with some simple trichomes. Flowers divaricate-ascending at anthesis; sepals usually sparsely pubescent, rarely glabrous; petals whitish to pale lavender, 4–6 × 1–1.5 mm, glabrous; pollen ellipsoid or spheroid. Fruits widely pendent, not appressed to rachis, not secund, curved to nearly straight, edges parallel, 2.2–4 cm × 1.2–2.1 mm; valves glabrous; ovules 40–70 (–90) per ovary; style 0.1–0.3 (–0.5) mm. Seeds biseriate, 0.9–1.2 × 0.6–0.9 mm, usually not winged. 2n = 14, 21.
Phenology: Flowering Apr–Jun.
Habitat: Rock outcrops, open gravelly flats and hillsides in sagebrush, pinyon-juniper, mountain mahogany, open conifer forests
Elevation: 1600-3100 m
Distribution
Ariz., Calif., Colo., Nev., Utah, Wyo.
Discussion
Although included in Arabis (Boechera) demissa by some authors (e.g., S. L. Welsh et al. 2003; N. H. Holmgren 2005b), B. pendulina is readily distinguished from that species (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). Typical collections are sexual diploids, whereas the type of var. russeola is a triploid apomict; further study is needed to determine if the two are conspecific.
Selected References
None.
Lower Taxa
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