Boechera formosa

(Greene) Windham & Al-Shehbaz

Harvard Pap. Bot. 11: 68. 2006.

Basionym: Arabis formosa Greene Pittonia 4: 198. 1900
Synonyms: Arabis pulchra var. pallens M. E. Jones Boechera pulchra subsp. pallens (M. E. Jones) W. A. Weber Boechera pulchra var. pallens (M. E. Jones) Dorn
Treatment appears in FNA Volume 7. Treatment on page 379. Mentioned on page 352, 375, 393, 400.

Perennials; long-lived; sexual; caudex woody. Stems usually 1 per caudex branch, arising from center of leaf tuft, above ground surface on woody base, 2–5.5 dm, densely pubescent proximally, trichomes short-stalked, 4–7-rayed, 0.1–0.4 mm, similarly pubescent distally. Basal leaves: blade linear to linear-oblanceolate, 2–3 (–4) mm wide, margins entire, sometimes ciliate near petiole base, trichomes (simple or 2-rayed), to 0.8 mm, surfaces densely pubescent, trichomes short-stalked, 4–8-rayed, 0.1–0.3 mm. Cauline leaves: 7–18, concealing stem proximally; blade auricles absent, surfaces of distalmost leaves densely pubescent. Racemes 6–26-flowered, usually unbranched. Fruiting pedicels horizontal to descending, usually recurved, 5–10 (–20) mm, pubescent, trichomes appressed, branched. Flowers divaricate at anthesis; sepals pubescent; petals white to pale lavender, 8–18 × 2.5–4.4 (–5.5) mm, glabrous; pollen ellipsoid. Fruits divaricate-descending to reflexed, usually not appressed to rachis, rarely somewhat secund, straight, edges parallel, 4.3–7 cm × 1.6–3 mm; valves pubescent throughout; ovules 72–98 per ovary; style ca. 0.1 mm. Seeds biseriate, 1.2–1.6 × 1–1.2 mm; wing continuous, 0.1–0.2 mm wide. 2n = 14.


Phenology: Flowering Apr–Jun.
Habitat: Rocky slopes and sandy soil in blackbrush, sagebrush, and pinyon-juniper communities
Elevation: 1300-1900 m

Distribution

V7 527-distribution-map.gif

Ariz., Colo., N.Mex., Utah, Wyo.

Discussion

Although Boechera formosa is usually subsumed within Arabis (Boechera) pulchra, the two species are easily separated. Boechera formosa has white to lavender (versus mostly purple) petals, fruiting pedicels that are not abruptly recurved at the base, narrower (1.6–3 versus 2.5–4 mm wide), mostly non-appressed fruits, and narrower (1–1.2 versus 1.5–2.2 mm wide) seeds. The two taxa are separated by more than 500 km, with B. formosa found only on the Colorado Plateau and B. pulchra, in the strict sense, restricted to southern California, western Nevada, and northwestern Mexico.

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 formosa"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Greene) Windham & Al-Shehbaz +
not +  and rosulate +
Arabis formosa +
appendaged +  and unappendaged +
not +  and auriculate +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
linear;linear-oblanceolate +
much smaller +  and reduced +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Ariz. +, Colo. +, N.Mex. +, Utah +  and Wyo. +
4.3 cm43 mm <br />0.043 m <br /> (7 cm70 mm <br />0.07 m <br />) +
0.16 cm1.6 mm <br />0.0016 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
1300-1900 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
straight +
divaricate-descending +  and reflexed +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky slopes and sandy soil in blackbrush, sagebrush, and pinyon-juniper communities +
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 +
0.44 cm4.4 mm <br />0.0044 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
white +  and pale lavender +
8mm;18mm +
rudimentary +
oblanceolate +  and spatulate +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.44 cm4.4 mm <br />0.0044 m <br />) +
Flowering Apr–Jun. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
Harvard Pap. Bot. +
unbranched;6-26-flowered +
reflexed +, ascending +  and erect +
slender +
mucilaginous +
margined +, not winged +  and winged +
not +  and mucilaginous +
white +, black +, brown +  and yellow +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
orbicular +, oblong +  and flattened +
0.1 cm1 mm <br />0.001 m <br /> (0.12 cm1.2 mm <br />0.0012 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 +
0.1 cm1 mm <br />0.001 m <br /> (?) +
Arabis pulchra var. pallens +, Boechera pulchra subsp. pallens +  and Boechera pulchra var. pallens +
Boechera formosa +
Boechera +
species +
branched +  and short-stalked +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
perennial +  and long-lived +
recurved +, horizontal +  and descending +
0.5 cm5 mm <br />0.005 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;0.2mm +