Boechera consanguinea |
Boechera cascadensis |
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Four Corners rockcress |
Cascade rock-cress, Cascade suncress, Cascades rockcress, littleleaf rockcress |
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Habit | Biennials or perennials; short-lived; apomictic; caudex present or absent. | Perennials; long-lived; (cespitose); apomictic; caudex somewhat woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 1.5–5 dm, densely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.2–0.5 mm, glabrous or sparsely pubescent distally. |
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. |
Basal leaves | blade oblanceolate, 2–10 mm wide, margins usually dentate, sometimes ciliate near petiole base, trichomes (usually spurred), to 0.7 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 4–8-rayed, 0.1–0.4 mm. |
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. |
Cauline leaves | 15–36, sometimes concealing stem proximally; blade auricles 1–3 mm, surfaces of distalmost leaves sparsely pubescent. |
4–6, not concealing stem; blade auricles 0.5–1 mm, surfaces of distalmost leaves glabrous. |
Racemes | 20–55-flowered, usually unbranched. |
3–11-flowered, unbranched. |
Flowers | divaricate-descending at anthesis; sepals pubescent; petals pale lavender, 5–8.5 × 1–2 mm, glabrous; pollen spheroid. |
ascending at anthesis; sepals glabrous or sparsely pubescent; petals lavender, 5–6 × 1–1.7 mm, glabrous; pollen spheroid. |
Fruiting pedicels | reflexed to divaricate-descending, usually curved downward, 8–14 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. |
ascending to divaricate-ascending, straight, 3–8 mm, glabrous. |
Fruits | reflexed to pendent, rarely appressed to rachis, not secund, straight or slightly curved, edges parallel, 4–6 cm × 1–2 mm; valves glabrous; ovules 100–128 per ovary; style 0.05–0.5 mm. |
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. |
Seeds | biseriate to sub-biseriate, mature seeds not seen. |
uniseriate, 1.1–1.3 × 0.9–1 mm; wing continuous, 0.05–0.1 mm wide. |
Boechera consanguinea |
Boechera cascadensis |
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Phenology | Flowering May. | Flowering Jun. |
Habitat | Rocky slopes and sandy soil in ponderosa pine, pinyon-juniper, and sagebrush communities | Basaltic cliffs and rocky slopes in subalpine areas |
Elevation | 1900-2500 m (6200-8200 ft) | ca. 1900 m (ca. 6200 ft) |
Distribution |
CO; NM; UT
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OR; WA |
Discussion | Morphological evidence suggests that Boechera consanguinea is an apomictic species that arose through hybridization between B. fendleri and B. retrofracta. It is most similar to B. goodrichii, another apomictic hybrid involving B. retrofracta (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 371. | FNA vol. 7, p. 369. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis consanguinea, Arabis holboellii var. consanguinea | Arabis microphylla var. thompsonii |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 261. (2007) | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 260. (2007) |
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