Boechera dentata |
Boechera holboellii |
|
---|---|---|
Short's rockcress |
|
|
Habit | Biennials; short-lived; sexual; caudex present or absent. | Biennials or perennials; short-lived; apomictic or sexual; caudex present or absent. |
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. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 2–6.7 dm, densely pubescent proximally, trichomes short-stalked, 4–8-rayed, 0.1–0.3 mm, glabrous or sparsely pubescent 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, 2–5 mm wide, margins entire, sometimes ciliate near petiole base, trichomes (usually simple), to 0.7 mm, surfaces sparsely to moderately pubescent, trichomes short-stalked, 4–8-rayed, 0.1–0.3 mm. |
Cauline leaves | 4–20, rarely concealing stem; blade auricles 1–8 mm, surfaces of distalmost leaves sparsely pubescent. |
7–40, often concealing stem proximally; blade auricles 1–4 mm, surfaces of distalmost leaves glabrous or sparsely pubescent. |
Racemes | 14–66-flowered, sparingly branched. |
10–60-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. |
divaricate to pendent at anthesis; sepals pubescent; petals white, 4–8 × 1–2 mm, glabrous; pollen ellipsoid or spheroid. |
Fruiting pedicels | divaricate-ascending to slightly descending, straight, 1–6 mm, glabrous or pubescent, trichomes appressed, branched. |
descending to reflexed, most abruptly recurved near base, 5–10 mm, glabrous or sparsely pubescent, trichomes appressed, branched. |
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. |
descending to reflexed, not appressed to rachis, strongly secund, often curved, edges parallel, 0.35–0.65 cm × (2–)2.2–2.5 mm; valves glabrous; ovules 80–102 per ovary. |
Seeds | uniseriate, 0.7–1.1 × 0.5–0.6 mm; not winged. |
uniseriate to sub-biseriate, 1.4–1.7 × 1–1.2 mm; wing continuous, to 0.2 mm wide. |
2n | = 14, 21. |
|
Boechera dentata |
Boechera holboellii |
|
Phenology | Flowering Apr–Jun. | Flowering Jul–Aug. |
Habitat | Bluffs and rocky ledges, wooded slopes, floodplains | Rocky slopes and gravelly soil near coast |
Elevation | 100-300 m (300-1000 ft) | 100-300 m (300-1000 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
|
Greenland |
Discussion | Sisymbrium dentatum Torrey is an illegitimate name that pertains to Iodanthus dentatus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Both sexual diploid and apomictic triploid collections of Boechera holboellii are known; available data suggest that the triploid is an autopolyploid derivative of the sexual diploid but further study is needed. In the narrow circumscription adopted here, it appears to be restricted to Greenland (see discussion of B. quebecensis in M. D. Windham and I. A. Al-Shehbaz 2007b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 373. | FNA vol. 7, p. 384. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Shortia dentata, Arabis dentata var. phalacrocarpa, Arabis perstellata var. shortii, Arabis shortii, Arabis shortii var. phalacrocarpa, B. shortii, Iodanthus dentatus | Arabis holboellii, Arabis holboellii var. tenuis, B. tenuis |
Name authority | (Rafinesque) Al-Shehbaz & Zarucchi: Harvard Pap. Bot. 13: 293. (2008) | (Hornemann) Á. Löve & D. Löve: Bot. Not. 128: 513. (1976) |
Web links |