Boechera dentata |
Boechera johnstonii |
|
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Short's rockcress |
Johnston's rockcress |
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Habit | Biennials; short-lived; sexual; caudex present or absent. | Perennials; long-lived; (cespitose); sexual; caudex 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. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 0.5–2 dm, densely pubescent proximally, trichomes short-stalked, 4–10-rayed, 0.07–0.15 mm, sparsely to densely 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 narrowly oblanceolate, 1.5–4 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 6–14-rayed, 0.07–0.15 mm. |
Cauline leaves | 4–20, rarely concealing stem; blade auricles 1–8 mm, surfaces of distalmost leaves sparsely pubescent. |
4–10, often concealing stem proximally; blade auricles absent, surfaces of distalmost leaves densely pubescent. |
Racemes | 14–66-flowered, sparingly branched. |
10–18-flowered, 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 purple, 9–14 × 2–4 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | divaricate-ascending to slightly descending, straight, 1–6 mm, glabrous or pubescent, trichomes appressed, branched. |
divaricate-ascending, straight, 5–14 mm, 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. |
divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 4–6 cm × 2.5–4 mm; valves glabrous; ovules 26–34 per ovary; style (0.7–)1–2 mm. |
Seeds | uniseriate, 0.7–1.1 × 0.5–0.6 mm; not winged. |
uniseriate, 1.9–2.7 × 1.5–2.2 mm; wing continuous, 0.3–0.7 mm wide. |
Boechera dentata |
Boechera johnstonii |
|
Phenology | Flowering Apr–Jun. | Flowering Feb–Mar. |
Habitat | Bluffs and rocky ledges, wooded slopes, floodplains | Rocky areas and gravelly soil in chaparral and oak-pine savannas |
Elevation | 100-300 m (300-1000 ft) | 1300-1700 m (4300-5600 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
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CA |
Discussion | Sisymbrium dentatum Torrey is an illegitimate name that pertains to Iodanthus dentatus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Boechera johnstonii and B. hirshbergiae are too similar to be considered distinct species. Even with the expanded circumscription, this distinctive sexual species is known only from the area of Cuyamaca Lake (San Diego County) and the San Jacinto Mountains (Riverside County). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 373. | FNA vol. 7, p. 386. |
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 johnstonii, Arabis hirshbergiae, B. hirshbergiae |
Name authority | (Rafinesque) Al-Shehbaz & Zarucchi: Harvard Pap. Bot. 13: 293. (2008) | (Munz) Al-Shehbaz: Novon 13: 386. (2003) |
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