Boechera pallidifolia

(Rollins) W. A. Weber

Phytologia 79: 65. 1996.

Basionym: Arabis pallidifolia Rollins Cruciferae Continental N. Amer., 181. 1993
Synonyms: Arabis thompsonii S. L. Welsh Boechera thompsonii (S. L. Welsh) N. H. Holmgren
Treatment appears in FNA Volume 7. Treatment on page 392. Mentioned on page 362, 372, 375, 381, 393, 396, 411.

Perennials; short-lived; sexual; caudex usually not woody. Stems usually 2–5 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, (0.5–) 1.5–4 dm, densely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.1–0.3 mm, glabrous or sparsely pubescent distally. Basal leaves: blade oblanceolate to obovate, 5–11 (–13) mm wide, margins shallowly dentate or, sometimes, entire, often ciliate along petiole, trichomes (simple and 2-rayed), surfaces moderately pubescent, trichomes short-stalked, 4–8-rayed, 0.1–0.3 mm. Cauline leaves: 3–8 (–11), not concealing stem; blade auricles (0.5–) 1–2 mm, surfaces of distalmost leaves sparsely pubescent. Racemes 4–15 (–20) -flowered, usually unbranched. Fruiting pedicels ascending to divaricate-ascending, straight or, sometimes, recurved, 7–15 mm, glabrous or sparsely pubescent. Flowers ascending at anthesis; sepals pubescent; petals usually lavender, rarely whitish, 5–9 × 1.2–2.5 mm, glabrous; pollen ellipsoid. Fruits usually ascending, rarely horizontal, not appressed to rachis, not secund, straight to curved, edges parallel, 2.5–5 (–6.5) cm × 1–2 mm; valves glabrous; ovules 44–62 per ovary; style 0.05–0.4 mm. Seeds uniseriate, 1.1–1.3 × 1–1.1 mm; wing nearly continuous, 0.07–0.15 mm wide.


Phenology: Flowering Apr–Jun.
Habitat: Rocky slopes and sandy soil in pinyon-juniper, sagebrush communities
Elevation: 1600-2500 m

Distribution

V7 559-distribution-map.gif

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

Discussion

Although Boechera pallidifolia was originally described as endemic to west-central Colorado, recent studies favor a broader circumscription that includes sexual populations previously assigned to Arabis (Boechera) selbyi (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). The species has hybridized with nearly every sexual diploid within its range (including B. crandallii, B. fendleri, B. formosa, and B. pendulina), producing a confusing array of apomictic triploids including the type specimen of A. selbyi.

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 pallidifolia"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Rollins) W. A. Weber +
not +  and rosulate +
Arabis pallidifolia +
appendaged +  and unappendaged +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
not +  and auriculate +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate;obovate +
much smaller +  and reduced +
0.5 cm5 mm <br />0.005 m <br /> (1.1 cm11 mm <br />0.011 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. +
5 cm50 mm <br />0.05 m <br /> (6.5 cm65 mm <br />0.065 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
1600-2500 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
straight +  and curved +
horizontal +  and ascending +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky slopes and sandy soil in pinyon-juniper, sagebrush communities +
annular +  and semiannular +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
entire +, , +  and dentate +
pinnatifid +
prominent +  and obscure +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
rudimentary +
oblanceolate +  and spatulate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Flowering Apr–Jun. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
unbranched;4-15(-20)-flowered +
recurved +, ascending +  and divaricate-ascending +
pubescent +  and glabrous +
slender +
0.7 cm7 mm <br />0.007 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
mucilaginous +
margined +, not winged +  and winged +
biseriate +, sub-biseriate +  and uniseriate +
not +  and mucilaginous +
white +, black +, brown +  and yellow +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
orbicular +, oblong +  and flattened +
0.1 cm1 mm <br />0.001 m <br /> (0.11 cm1.1 mm <br />0.0011 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 +
2 +  and 5 +
subsessile +, sessile +  and petiolate +
persistent +
distinct +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
Arabis thompsonii +  and Boechera thompsonii +
Boechera pallidifolia +
Boechera +
species +
pubescent +  and glabrous +
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 +
perennial +  and short-lived +
hispid +, hirsute +, pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.07mm;0.15mm +