Boechera howellii

(S. Watson) Windham & Al-Shehbaz

Harvard Pap. Bot. 11: 69. 2006.

Basionym: Arabis howellii S. Watson Proc. Amer. Acad. Arts 25: 124. 1890
Synonyms: Arabis conferta Greene Arabis inamoena var. acutata Jepson Arabis platyloba Greene Arabis platysperma var. howellii (S. Watson) Jepson Arabis platysperma var. imparata Jepson
Treatment appears in FNA Volume 7. Treatment on page 384. Mentioned on page 351, 356, 372, 398.

Perennials; long-lived; sexual; caudex usually woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 0.6–2 (–3) dm, glabrous throughout. Basal leaves: blade narrowly oblanceolate, 1–7 mm wide, margins entire, ciliate proximally, trichomes (simple mixed with a few short-stalked, 2-rayed ones) 0.1–0.4 mm, surfaces glabrous. Cauline leaves: 2–4, not concealing stem; blade auricles (0–) 0.2–1 mm, surfaces of distalmost leaves usually glabrous, rarely ciliate proximally. Racemes 2–5-flowered, unbranched. Fruiting pedicels ascending, straight, 4–10 mm, glabrous. Flowers erect to ascending at anthesis; sepals glabrous; petals white to dark lavender, 4–8 × 1–2.5 mm, glabrous; pollen ellipsoid. Fruits suberect to ascending, usually not appressed to rachis, not secund, straight to curved, edges often somewhat undulate (not parallel), 2.5–6.5 cm × 3–7 mm; valves glabrous; ovules 10–20 per ovary; style 0.05–0.3 mm. Seeds uniseriate, 3–6 × 2–4 mm; wing continuous, 1.3–2.5 mm wide.


Phenology: Flowering Jun–Aug.
Habitat: Rock outcrops, talus slopes and gravelly soil in alpine and subalpine habitats
Elevation: 1800-3800 m

Discussion

Boechera howellii usually is subsumed under B. platysperma, but the two taxa are distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 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."dm" is not declared as a valid unit of measurement for this property.

... more about "Boechera howellii"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(S. Watson) Windham & Al-Shehbaz +
not +  and rosulate +
Arabis howellii +
appendaged +  and unappendaged +
0 cm0 mm <br />0 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
not +  and auriculate +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate +
much smaller +  and reduced +
0.1 cm1 mm <br />0.001 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Calif. +, Nev. +  and Oreg. +
2.5 cm25 mm <br />0.025 m <br /> (6.5 cm65 mm <br />0.065 m <br />) +
undulate +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1800-3800 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
erect +  and ascending +
straight +  and curved +
suberect +  and ascending +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rock outcrops, talus slopes and gravelly soil in alpine and subalpine habitats +
annular +  and semiannular +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
pinnatifid +
prominent +  and obscure +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
white +  and dark lavender +
rudimentary +
oblanceolate +  and spatulate +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Flowering Jun–Aug. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
Harvard Pap. Bot. +
unbranched;2-5-flowered +
slender +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
mucilaginous +
margined +, not winged +  and winged +
biseriate +, sub-biseriate +  and uniseriate +
not +  and mucilaginous +
white +, black +, brown +  and yellow +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
orbicular +, oblong +  and flattened +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 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 +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
Arabis conferta +, Arabis inamoena var. acutata +, Arabis platyloba +, Arabis platysperma var. howellii +  and Arabis platysperma var. imparata +
Boechera howellii +
Boechera +
species +
dendritic +, branched +  and simple +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
perennial +  and long-lived +
hispid +, hirsute +, pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
1.3mm;2.5mm +