Boechera divaricarpa

(A. Nelson) Á. Löve & D. Löve

Bot. Not. 128: 513. 1976.

Basionym: Arabis divaricarpa A. Nelson Bot. Gaz. 30: 193. 1900
Synonyms: Arabis stokesiae Rydberg
Treatment appears in FNA Volume 7. Treatment on page 374. Mentioned on page 349, 356, 363, 365, 382.

Biennials or perennials; short-lived; apomictic; caudex present or absent. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, (1.5–) 3–9 dm, glabrous or pubescent proximally, trichomes sessile, 2–4-rayed (some simple), to 0.7 mm, glabrous distally. Basal leaves: blade oblanceolate, 2–10 mm wide, margins usually entire, rarely denticulate, ciliate along petiole, trichomes (simple), to 0.8 mm, surfaces sparsely to densely pubescent, trichomes sessile, 2–6-rayed, 0.1–0.4 mm. Cauline leaves: (10–) 15–56, concealing stem proximally; blade auricles 1–5 mm, surfaces of distalmost leaves glabrous. Racemes 12–40 (–65) -flowered, usually unbranched. Fruiting pedicels divaricate-ascending to horizontal, straight, 5–12 mm, glabrous. Flowers divaricate-ascending at anthesis; sepals glabrous or with scattered trichomes; petals usually purple, rarely lavender, 6–9 × 1.5–3 mm, glabrous; pollen spheroid. Fruits divaricate-ascending to horizontal, not appressed to rachis, not secund, straight, edges parallel, (4.5–) 5.5–11 cm × 1.7–2.5 mm; valves glabrous; ovules 114–142 per ovary; style 0.05–0.2 mm. Seeds uniseriate to sub-biseriate, 1.4–2 × 1–1.5 mm; wing continuous, 0.1–0.2 mm wide. 2n = 21.


Phenology: Flowering May–Jul.
Habitat: Rock outcrops, talus slopes and gravelly hillsides in sagebrush, mountain shrub, and open conifer forests
Elevation: 900-2500 m

Distribution

V7 515-distribution-map.gif

Calif., Idaho, Mont., Nev., Utah, Wash., Wyo.

Discussion

The name Arabis (Boechera) divaricarpa has been applied to nearly every hybrid containing a genome derived from B. stricta. This presents a serious barrier to understanding the evolution of Boechera and also is contrary to the International Code of Botanical Nomenclature, because some names usually placed in synonymy (i.e., B. grahamii and B. brachycarpa) have priority at species level (M. D. Windham and I. A. Al-Shehbaz 2007b). To address this problem, we treat the following as distinct species: B. acutina, B. grahamii (= B. brachycarpa of R. D. Dorn 2001), and B. pratincola (all considered synonyms of A. divaricarpa by R. C. Rollins 1993), and B. calderi, B. elkoensis, and B. quebecensis (taxa described after 1993). Detailed comparison among these taxa are provided by Windham and Al-Shehbaz (2007, 2007b). The narrow concept of B. divaricarpa advocated here encompasses apomictic triploid populations containing three distinct genomes, one each derived from B. retrofracta, B. sparsiflora, and B. stricta. If the species is defined more broadly, the name B. grahamii has priority.

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 divaricarpa"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(A. Nelson) Á. Löve & D. Löve +
not +  and rosulate +
Arabis divaricarpa +
appendaged +  and unappendaged +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate +
much smaller +  and reduced +
2mm;10mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Calif. +, Idaho +, Mont. +, Nev. +, Utah +, Wash. +  and Wyo. +
4.5 cm45 mm <br />0.045 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
5.5 cm55 mm <br />0.055 m <br /> (11 cm110 mm <br />0.11 m <br />) +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
900-2500 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
divaricate-ascending +
straight +
divaricate-ascending +  and horizontal +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rock outcrops, talus slopes and gravelly hillsides in sagebrush, mountain shrub, and open conifer forests +
annular +  and semiannular +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
denticulate +
prominent +  and obscure +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
Magenta (?) +, Red (?) +, Yellowish (?) +, Purple (?) +, Lavender (?) +, Pink (?) +  and White (?) +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
rudimentary +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Flowering May–Jul. +
trinucleate +  and 3(-11)-colpate +
spheroid +
unbranched;12-40(-65)-flowered +
elongated +
divaricate-ascending +  and horizontal +
slender +
0.5 cm5 mm <br />0.005 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
mucilaginous +
margined +, not winged +  and winged +
uniseriate +  and sub-biseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
orbicular +, oblong +  and flattened +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
persistent +  and caducous +
distinct +
spreading +, ascending +  and erect +
with scattered trichomes +  and glabrous +
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 /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
glabrous +  and pubescent +
Arabis stokesiae +
Boechera divaricarpa +
Boechera +
species +
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 +, short-lived +  and biennial +
hispid +, hirsute +, pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.1mm;0.2mm +