Boechera acutina

(Greene) Windham & Al-Shehbaz

Harvard Pap. Bot. 12: 236. 2007.

Basionym: Arabis acutina Greene Leafl. Bot. Observ. Crit. 2: 82. 1910
Synonyms: Arabis divaricarpa var. interposita (Greene) Rollins Arabis drummondii var. interposita (Greene) Rollins Arabis interposita Greene
Treatment appears in FNA Volume 7. Treatment on page 365. Mentioned on page 362, 374.

Biennials or perennials; short-lived; apomictic; caudex present or absent. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 1.5–6 dm, densely pubescent proximally, trichomes sessile, 2–4-rayed, 0.15–0.4 mm, usually sparsely pubescent distally, rarely glabrous. Basal leaves: blade oblanceolate, 1.5–6 mm wide, margins usually entire, rarely denticulate, ciliate proximally, trichomes (simple), to 0.5 mm, surfaces sparsely to moderately pubescent, trichomes sessile, 3–5 (or 6) -rayed, 0.15–0.35 mm. Cauline leaves: 2–20 (–38), often concealing stem proximally; blade auricles 0.3–2 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. Racemes 5–20 (–36) -flowered, usually unbranched. Fruiting pedicels erect to ascending, usually straight, 3–10 mm, pubescent or glabrous, trichomes appressed, branched. Flowers ascending at anthesis; sepals pubescent; petals white or lavender, 5–7 × 0.9–1.3 mm, glabrous; pollen spheroid. Fruits ascending, not appressed to rachis, not secund, straight, edges parallel, 2.5–7.5 cm × 1.2–1.8 mm; valves glabrous; ovules 46–100 per ovary; style 0.3–1 mm. Seeds uniseriate, 1.8–2.2 × 1–1.4 mm; wing continuous, 0.1–0.4 mm wide.


Phenology: Flowering Jun–Jul.
Habitat: Gravelly slopes in meadows, open forests
Elevation: 1400-1900 m

Discussion

Boechera acutina is an apomictic hybrid that clearly contains a genome derived from B. stricta; the other parent remains uncertain. Plants of B. acutina are superficially similar to B. pratincola and are often misidentified as Arabis (Boechera) divaricarpa; the species is easily distinguished from both of those (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison).

Selected References

None.

Lower Taxa

None.

"elongated" is not a number."thick" is not a number."dm" is not declared as a valid unit of measurement for this property.

... more about "Boechera acutina"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Greene) Windham & Al-Shehbaz +
not +  and rosulate +
Arabis acutina +
appendaged +  and unappendaged +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate +
much smaller +  and reduced +
1.5mm;6mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Calif. +, Idaho +  and Oreg. +
2.5 cm25 mm <br />0.025 m <br /> (7.5 cm75 mm <br />0.075 m <br />) +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
1400-1900 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
straight +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Gravelly slopes in meadows, open forests +
annular +  and semiannular +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
denticulate +
prominent +  and obscure +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
rudimentary +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
Flowering Jun–Jul. +
trinucleate +  and 3(-11)-colpate +
spheroid +
Harvard Pap. Bot. +
unbranched;5-20(-36)-flowered +
elongated +
reflexed +, ascending +  and erect +
slender +
mucilaginous +
margined +, not winged +  and winged +
biseriate +, sub-biseriate +  and uniseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
orbicular +, oblong +  and flattened +
0.1 cm1 mm <br />0.001 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
persistent +  and caducous +
distinct +
spreading +, ascending +  and erect +
oblong +  and ovate +
reduced +
latiseptate +, schizocarpic +, samaroid +  and lomentaceous +
indehiscent +  and dehiscent +
angustiseptate +, flat +, angled +, terete +, torulose +, not +, segmented +  and nutletlike +
tetradynamous +
branched +  and unbranched +
procumbent +  and decumbent +
subsessile +, sessile +  and petiolate +
persistent +
distinct +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
glabrous +  and pubescent +
Arabis divaricarpa var. interposita +, Arabis drummondii var. interposita +  and Arabis interposita +
Boechera acutina +
Boechera +
species +
branched +  and sessile +
glabrous +  and pubescent +
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.035 cm0.35 mm <br />3.5e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
perennial +, short-lived +  and biennial +
erect +  and ascending +
glabrous +  and pubescent +
0.3 cm3 mm <br />0.003 m <br /> (1 cm10 mm <br />0.01 m <br />) +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.1mm;0.4mm +