Boechera cascadensis |
Boechera parishii |
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Cascade rock-cress, Cascade suncress, Cascades rockcress, littleleaf rockcress |
dwarf rockcress, Parish's Rock cress |
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Habit | Perennials; long-lived; (cespitose); apomictic; caudex somewhat woody. | Perennials; short- to long-lived; sexual; caudex often woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 0.5–2.2 dm, sparsely pubescent proximally, trichomes simple and short-stalked, 2- or 3-rayed, 0.1–0.2 mm, glabrous distally. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 0.3–1.4 dm, densely pubescent proximally, trichomes short-stalked, 2–8-rayed, 0.2–0.4 mm, sparsely pubescent distally. |
Basal leaves | blade linear-oblanceolate, 0.7–2 mm wide, margins entire, ciliate proximally, trichomes to 0.4 mm, surfaces densely pubescent, trichomes short-stalked, (2- or) 3–6-rayed, 0.05–0.2(–0.3) mm. |
blade linear to linear-oblanceolate, 0.5–2 mm wide, margins entire, often ciliate along petiole, trichomes (branched), to 0.6 mm, surfaces densely pubescent, trichomes short-stalked, 6–12-rayed, 0.07–0.15 mm. |
Cauline leaves | 4–6, not concealing stem; blade auricles 0.5–1 mm, surfaces of distalmost leaves glabrous. |
2–8, rarely concealing stem proximally; blade auricles absent, surfaces of distalmost leaves densely pubescent. |
Racemes | 3–11-flowered, unbranched. |
5–20-flowered, unbranched. |
Flowers | ascending at anthesis; sepals glabrous or sparsely pubescent; petals lavender, 5–6 × 1–1.7 mm, glabrous; pollen spheroid. |
ascending at anthesis; sepals pubescent; petals lavender to purple, 8–13 × 2.5–4 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | ascending to divaricate-ascending, straight, 3–8 mm, glabrous. |
ascending, straight, 3–7 mm, pubescent, trichomes appressed, branched. |
Fruits | ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 3.5–6.2 cm × 1.2–1.5 mm; valves glabrous; ovules 58–80 per ovary; style 0.8–1.5 mm. |
ascending, not appressed to rachis, not secund, straight, edges parallel, 1.5–2.5 cm × 1.8–2.5 mm; valves glabrous; ovules 12–20 per ovary; style 3–8 mm. |
Seeds | uniseriate, 1.1–1.3 × 0.9–1 mm; wing continuous, 0.05–0.1 mm wide. |
uniseriate, 1.5–2 × 1–1.5 mm; wing distal or continuous, 0.05–0.2 mm wide. |
2n | = 14. |
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Boechera cascadensis |
Boechera parishii |
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Phenology | Flowering Jun. | Flowering Mar–May. |
Habitat | Basaltic cliffs and rocky slopes in subalpine areas | Gravelly hillsides in sagebrush- juniper-pine areas |
Elevation | ca. 1900 m (ca. 6200 ft) | 1900-2300 m (6200-7500 ft) |
Distribution |
OR; WA |
CA
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Discussion | Of conservation concern. Morphological evidence suggests that Boechera cascadensis is an apomictic species that arose through hybridization between B. microphylla and B. paupercula (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). It is known from two collections: the type specimens from Kittitas County, Washington, and a more recent collection from Baker County, Oregon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Boechera parishii is a distinctive, long-styled, sexual diploid known only from San Bernardino Mountains in San Bernardino County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 369. | FNA vol. 7, p. 393. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis microphylla var. thompsonii | Arabis parishii |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 260. (2007) | (S. Watson) Al-Shehbaz: Novon 13: 388. (2003) |
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