Boechera dentata |
Boechera gracilenta |
|
---|---|---|
Short's rockcress |
Selby's rockcress |
|
Habit | Biennials; short-lived; sexual; caudex present or absent. | Perennials; short- or (rarely) long-lived; apomictic; caudex usually not woody. |
Stems | usually 2–4 per plant or caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 2–6 dm, pubescent proximally, trichomes short-stalked, 2–4-rayed, 0.15–0.4 mm, sparsely pubescent or glabrous distally. |
1–9 per caudex branch, arising from center or margin of rosette near ground surface, (1.5–)2.5–5.5 dm, densely pubescent proximally, trichomes short-stalked, 2–4-rayed, 0.1–0.5 mm, mixed with some simple ones, to 0.8 mm, glabrous distally. |
Basal leaves | blade obovate to oblanceolate, (6–)10–45 mm wide, margins dentate, not ciliate, surfaces sparsely pubescent, abaxially trichomes short-stalked, 3- or 4-rayed, 0.15–0.4 mm, adaxially simple ones, 0.4–1 mm. |
blade oblanceolate, 2–9 mm wide, margins shallowly dentate or sometimes entire, ciliate proximally, trichomes (simple and spurred), to 1.2 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 4–6(–8)-rayed, 0.1–0.5 mm. |
Cauline leaves | 4–20, rarely concealing stem; blade auricles 1–8 mm, surfaces of distalmost leaves sparsely pubescent. |
4–9, not concealing stem; blade auricles 1–3 mm, surfaces of distalmost leaves usually glabrous. |
Racemes | 14–66-flowered, sparingly branched. |
7–20-flowered, usually unbranched. |
Flowers | divaricate at anthesis; sepals glabrous or sparsely pubescent; petals white or cream, 2–3.5 × 0.7–1 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals lavender, 6–7 × 1.5–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | divaricate-ascending to slightly descending, straight, 1–6 mm, glabrous or pubescent, trichomes appressed, branched. |
divaricate-ascending, gently curved downward, (7–)10–18 mm, glabrous. |
Fruits | divaricate-ascending to slightly descending, not appressed to rachis, not secund, straight or slightly curved, edges parallel, 1.3–4.2 cm × 0.7–0.8 mm; valves usually sparsely pubescent throughout, rarely glabrous; ovules 14–44 per ovary; style 0.1–0.5 mm. |
usually widely pendent, rarely horizontal, not appressed to rachis, not secund, slightly curved, edges parallel, (3–)4.5–7 cm × 1.7–2 mm; valves glabrous; ovules 60–96 per ovary; style 0.1–0.3 mm. |
Seeds | uniseriate, 0.7–1.1 × 0.5–0.6 mm; not winged. |
sub-biseriate, 1.2–1.8 × 0.9–1.2 mm; wing continuous, 0.1–0.25 mm wide. |
Boechera dentata |
Boechera gracilenta |
|
Phenology | Flowering Apr–Jun. | Flowering Apr–May. |
Habitat | Bluffs and rocky ledges, wooded slopes, floodplains | Rocky slopes and sandy soil in pinyon-juniper woodlands and mountain shrub communities |
Elevation | 100-300 m (300-1000 ft) | 1900-2300 m (6200-7500 ft) |
Distribution |
AL; AR; DC; IA; IL; IN; KS; KY; MD; MI; MN; MO; NE; NY; OH; OK; PA; SD; TN; VA; WI; WV; ON
|
AZ; CO; NM; UT
|
Discussion | Sisymbrium dentatum Torrey is an illegitimate name that pertains to Iodanthus dentatus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Morphological evidence suggests that Boechera gracilenta is an apomictic species that arose through hybridization between B. fendleri and B. pallidifolia; it is superficially similar to the sexual diploid B. perennans but is not closely related (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 373. | FNA vol. 7, p. 381. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Shortia dentata, Arabis dentata var. phalacrocarpa, Arabis perstellata var. shortii, Arabis shortii, Arabis shortii var. phalacrocarpa, B. shortii, Iodanthus dentatus | Arabis gracilenta, Arabis selbyi, B. selbyi |
Name authority | (Rafinesque) Al-Shehbaz & Zarucchi: Harvard Pap. Bot. 13: 293. (2008) | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 240. (2007) |
Web links |