Boechera canadensis |
Boechera holboellii |
|
---|---|---|
sicklepod, sicklepod rockcress |
|
|
Habit | Biennials; short-lived; sexual; caudex not evident. | Biennials or perennials; short-lived; apomictic or sexual; caudex present or absent. |
Stems | 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. |
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, 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. |
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 | 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. |
7–40, often concealing stem proximally; blade auricles 1–4 mm, surfaces of distalmost leaves glabrous or sparsely pubescent. |
Racemes | 15–65(–82)-flowered, sometimes branched. |
10–60-flowered, usually unbranched. |
Flowers | divaricate-ascending to horizontal at anthesis; sepals pubescent; petals white, 3–5 × 0.7–1.2 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 | descending to horizontal, usually curved, rarely straight, 6–13(–17) mm, pubescent or glabrous, trichomes subappressed, usually 2-rayed. |
descending to reflexed, most abruptly recurved near base, 5–10 mm, glabrous or sparsely pubescent, trichomes appressed, branched. |
Fruits | 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. |
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, 1.7–3.5 × 1.5–2.2 mm; wing continuous, 0.4–1 mm wide distally. |
uniseriate to sub-biseriate, 1.4–1.7 × 1–1.2 mm; wing continuous, to 0.2 mm wide. |
2n | = 14. |
= 14, 21. |
Boechera canadensis |
Boechera holboellii |
|
Phenology | Flowering Apr–Jul. | Flowering Jul–Aug. |
Habitat | Bluffs, rocky slopes, ravines, open woods | Rocky slopes and gravelly soil near coast |
Elevation | 0-1200 m (0-3900 ft) | 100-300 m (300-1000 ft) |
Distribution |
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
|
Greenland |
Discussion | 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. 369. | FNA vol. 7, p. 384. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis canadensis, Arabis falcata, Arabis hirsuta var. ovata, Arabis ovata | Arabis holboellii, Arabis holboellii var. tenuis, B. tenuis |
Name authority | (Linnaeus) Al-Shehbaz: Novon 13: 384. (2003) | (Hornemann) Á. Löve & D. Löve: Bot. Not. 128: 513. (1976) |
Web links |