Boechera collinsii

(Fernald) Á. Löve & D. Löve

Taxon 31: 125. 1982.

Basionym: Arabis collinsii Fernald Rhodora 7: 32. 1905
Synonyms: Arabis holboellii var. collinsii (Fernald) Rollins Arabis retrofracta var. collinsii (Fernald) B. Boivin
Treatment appears in FNA Volume 7. Treatment on page 370. Mentioned on page 357, 371, 382, 389.

Perennials; usually short-lived; sexual; caudex not woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, (1.5–) 2.5–8 dm, densely pubescent proximally, trichomes simple and short-stalked, 2-rayed, to 1 mm, sparsely pubescent or glabrous distally. Basal leaves: blade oblanceolate, 1–7 mm wide, margins entire or dentate, ciliate along petiole, trichomes (simple), to 0.7 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 5–8-rayed, 0.15–0.4 mm. Cauline leaves: (8–) 15–40, concealing stem proximally; blade auricles 1–3 mm, surfaces of distalmost leaves usually sparsely pubescent. Racemes (15–) 30–90-flowered, usually unbranched. Fruiting pedicels reflexed, abruptly recurved at base, otherwise straight, 4–13 mm, glabrous or sparsely pubescent, trichomes usually simple. Flowers descending to pendent at anthesis; sepals pubescent; petals usually white, rarely lavender, 4–6 × 0.8–1.5 mm, glabrous; pollen ellipsoid. Fruits strongly reflexed, usually appressed to rachis, rarely somewhat secund, straight, edges parallel, 3.5–6 cm × 0.9–1.5 mm; valves glabrous; ovules 70–126 per ovary; style 0.2–0.5 mm. Seeds uniseriate, 1–1.4 × 0.8–1 mm; wing continuous (rarely absent), to 0.1 mm wide. 2n = 14.


Phenology: Flowering May–Jun.
Habitat: Rocky and gravelly hillsides, prairies, open woods, floodplains
Elevation: 600-1400 m

Distribution

V7 505-distribution-map.gif

Alta., Man., Que., Sask., Idaho, Minn., Mont., Nebr., N.Dak., S.Dak., Wyo.

Discussion

Though often treated as a variety of Arabis (Boechera) holboellii (e.g., R. C. Rollins 1993; G. A. Mulligan 1996), B. collinsii is easily distinguished from that species by having simple and 2-rayed (versus 4–8-rayed) trichomes proximally on stems, and narrower (0.9–1.5 versus 2–2.5 mm) usually non-secund fruits. The two taxa also show allopatric distributions, with B. collinsii found on the North American continent (usually east of the Rocky Mountains) and B. holboellii apparently confined to Greenland.

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 collinsii"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Fernald) Á. Löve & D. Löve +
not +  and rosulate +
straight +
recurved +  and reflexed +
pubescent +  and glabrous +
0.4 cm4 mm <br />0.004 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
Arabis collinsii +
appendaged +  and unappendaged +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate +
much smaller +  and reduced +
1mm;7mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
not woody +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Alta. +, Man. +, Que. +, Sask. +, Idaho +, Minn. +, Mont. +, Nebr. +, N.Dak. +, S.Dak. +  and Wyo. +
3.5 cm35 mm <br />0.035 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
600-1400 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
descending +  and pendent +
straight +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky and gravelly hillsides, prairies, open woods, floodplains +
annular +  and semiannular +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
dentate +  and entire +
pinnatifid +
prominent +  and obscure +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
rudimentary +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Flowering May–Jun. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
unbranched;(15-)30-90-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 (?) +
0.1 cm1 mm <br />0.001 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
orbicular +, oblong +  and flattened +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.1 cm1 mm <br />0.001 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 />) +
Arabis holboellii var. collinsii +  and Arabis retrofracta var. collinsii +
Boechera collinsii +
Boechera +
species +
simple +  and short-stalked +
glabrous +  and pubescent +
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-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 +
0mm;0.1mm +