Boechera atrorubens

(Suksdorf ex Greene) Windham & Al-Shehbaz

Harvard Pap. Bot. 11: 64. 2006.

Basionym: Arabis atrorubens Suksdorf ex Greene Erythea 1: 223. 1893
Synonyms: Arabis atriflora Suksdorf Arabis sparsiflora var. atrorubens (Suksdorf ex Greene) Rollins
Treatment appears in FNA Volume 7. Treatment on page 366. Mentioned on page 363, 367, 407.

Perennials; usually short-lived; sexual; caudex not woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 0.8–6 dm, sparsely pubescent proximally, trichomes short-stalked and simple, (scattered), 2-rayed, 0.1–0.15 mm, glabrous distally. Basal leaves: blade oblanceolate, 4–10 mm wide, margins usually dentate, not ciliate, surfaces densely pubescent, trichomes short-stalked, 3-rayed or 4-rayed, 0.1–0.2 mm. Cauline leaves: 7–25, concealing stem proximally; blade auricles 1–4 mm, surfaces of distalmost leaves glabrous. Racemes 6–20-flowered, usually unbranched. Fruiting pedicels ascending, usually straight, 5–10 mm, glabrous or pubescent, trichomes spreading, simple. Flowers ascending at anthesis; sepals pubescent; petals dark reddish purple (drying indigo), 7–9 × 1.5–2 mm, glabrous; pollen ellipsoid. Fruits ascending, not appressed to rachis, not secund, curved or straight, edges parallel, (4–) 6–12 cm × 1.7–2.2 mm; valves glabrous; ovules 80–100 per ovary; style 0.2–0.5 mm. Seeds uniseriate, 1.2–1.7 × 0.9–1.2 mm; wing lateral and distal, 0.1–0.2 mm wide.


Phenology: Flowering Apr–May.
Habitat: Rocky summits and sandy loam on sagebrush slopes
Elevation: ca. 600 m

Discussion

Boechera atrorubens is often treated as a variety of B. sparsiflora (e.g., R. C. Rollins 1993), it is readily separated from that species by having proximal stems sparsely (versus densely) pubescent with much smaller (0.15 versus 1.5 mm) trichomes. The two taxa rarely grow in proximity and, in areas where they are sympatric, B. atrorubens is further distinguished by its narrower (1.5–2 versus 2–5 mm) petals that are dark reddish purple to indigo (versus lavender or white).

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 atrorubens"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Suksdorf ex Greene) Windham & Al-Shehbaz +
not +  and rosulate +
Arabis atrorubens +
appendaged +  and unappendaged +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate +
much smaller +  and reduced +
4mm;10mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
not woody +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Oreg. +  and Wash. +
4 cm40 mm <br />0.04 m <br /> (6 cm60 mm <br />0.06 m <br />) +
6 cm60 mm <br />0.06 m <br /> (12 cm120 mm <br />0.12 m <br />) +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
ca. 600 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
straight +  and curved +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky summits and sandy loam on sagebrush slopes +
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 +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
rudimentary +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Flowering Apr–May. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
Harvard Pap. Bot. +
unbranched;6-20-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 (?) +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.17 cm1.7 mm <br />0.0017 m <br />) +
orbicular +, oblong +  and flattened +
0.09 cm0.9 mm <br />9.0e-4 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 +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
glabrous +  and pubescent +
Arabis atriflora +  and Arabis sparsiflora var. atrorubens +
Boechera atrorubens +
Boechera +
species +
simple +  and short-stalked +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
perennial +  and short-lived +
pubescent +  and glabrous +
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 +