Boechera oxylobula |
Boechera canadensis |
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sicklepod, sicklepod rockcress |
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Habit | Perennials; short- to long-lived; (cespitose); sexual; caudex usually not woody. | Biennials; short-lived; sexual; caudex not evident. |
Stems | usually 3–7 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.4–2.5 dm, glabrous or pubescent proximally, trichomes simple and short-stalked, 2-rayed, 0.1–0.4 mm, glabrous distally. |
1 per plant, arising from center of rosette near ground surface, 2.5–10(–12.5) dm, sparsely to densely pubescent proximally, trichomes simple, to 1 mm, glabrous or sparsely pubescent distally. |
Basal leaves | blade linear to linear-oblanceolate, 1–2.5 mm wide, margins usually entire, rarely denticulate, often ciliate, trichomes (simple), 0.3–0.7 mm, surfaces glabrous or sparsely pubescent, trichomes short-stalked, 2- or 3-rayed, 0.1–0.4 mm. |
blade obovate to oblanceolate, 10–30 mm wide, margins dentate, ciliate proximally, trichomes simple, to 1 mm, surfaces moderately pubescent, trichomes simple, 0.5–1.5 mm, these mixed with smaller, 2- or 3-rayed ones. |
Cauline leaves | 3–12, not concealing stem; blade auricles absent, surfaces of distalmost leaves usually glabrous, rarely sparsely pubescent. |
12–20, often concealing stem proximally; blade auricles absent or proximalmost blades with auricles 0.5–2(–5) mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 2–12-flowered, unbranched. |
15–65(–82)-flowered, sometimes branched. |
Flowers | ascending-divaricate at anthesis; sepals glabrous or pubescent; petals white to pale lavender, 4–5 × 1.5–2 mm, glabrous; pollen ellipsoid. |
divaricate-ascending to horizontal at anthesis; sepals pubescent; petals white, 3–5 × 0.7–1.2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | divaricate-ascending to horizontal, slightly to strongly recurved, 3–8 mm, glabrous or sparsely pubescent, trichomes (isolated), simple. |
descending to horizontal, usually curved, rarely straight, 6–13(–17) mm, pubescent or glabrous, trichomes subappressed, usually 2-rayed. |
Fruits | pendent, not appressed to rachis, not or, rarely, weakly secund, straight, edges parallel, 1.5–3.5 cm × 1.2–2 mm; valves glabrous; ovules 28–44 per ovary; style 0.1–0.4 mm. |
pendent to horizontal, not appressed to rachis, often secund, curved, edges parallel, 4–10 cm × 2.5–4 mm; valves glabrous; ovules 40–62 per ovary; style 0.3–0.8(–1.1) mm. |
Seeds | uniseriate, 0.9–1.2 × 0.6–1 mm; wing often continuous, 0.07–0.1 mm wide. |
uniseriate, 1.7–3.5 × 1.5–2.2 mm; wing continuous, 0.4–1 mm wide distally. |
2n | = 14. |
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Boechera oxylobula |
Boechera canadensis |
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Phenology | Flowering May–Jul. | Flowering Apr–Jul. |
Habitat | Cliffs, rocky slopes, gravelly soil in sagebrush and open conifer forests | Bluffs, rocky slopes, ravines, open woods |
Elevation | 2100-3600 m (6900-11800 ft) | 0-1200 m (0-3900 ft) |
Distribution |
CO |
AL; AR; CT; DC; FL; GA; IA; IL; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; NE; NY; OH; OK; PA; TN; TX; VA; VT; WI; WV; QC
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Discussion | Most of the collections assigned here have been called Arabis (Boechera) demissa by other authors (e.g., R. C. Rollins 1993; N. H. Holmgren 2005b). Because the holotype of A. demissa is identical to B. oxylobula in nearly every way (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison), we treat them as conspecific. Boechera oxylobula is restricted to Garfield, Gunnison, Hinsdale, Lake, Mineral, Park, and Saguache counties in central Colorado. The taxon traditionally treated as A. (Boechera) demissa var. languida is here recognized as an apomictic species of hybrid origin (see Windham and Al-Shehbaz 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 7, p. 391. | FNA vol. 7, p. 369. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis oxylobula, Arabis aprica, Arabis demissa, Arabis rugocarpa, B. demissa | Arabis canadensis, Arabis falcata, Arabis hirsuta var. ovata, Arabis ovata |
Name authority | (Greene) W. A. Weber: Phytologia 51: 370. (1982) | (Linnaeus) Al-Shehbaz: Novon 13: 384. (2003) |
Web links |