Boechera arcuata

(Nuttall) Windham & Al-Shehbaz

Harvard Pap. Bot. 11: 64. 2006.

Basionym: Streptanthus arcuatus Nuttall in J. Torrey and A. Gray, Fl. N. Amer. 1: 77. 1838
Synonyms: Arabis holboellii var. arcuata (Nuttall) Jepson Arabis maxima Greene Arabis sparsiflora var. arcuata (Nuttall) Rollins
Treatment appears in FNA Volume 7. Treatment on page 365. Mentioned on page 364, 367, 369, 404, 407.

Perennials; usually long-lived; sexual; caudex often woody (well-developed). Stems usually 1 per caudex branch, arising from center of rosette, elevated on woody base or from ground surface, (2–) 3–8 dm, densely pubescent proximally, trichomes short-stalked, 2-rayed and simple, to 1 mm, pubescent distally. Basal leaves: blade linear to oblanceolate, 2–7 (–12) mm wide, margins usually entire, rarely denticulate, ciliate along petiole, trichomes to 1.5 mm, surfaces densely pubescent, trichomes usually short-stalked, 2–5-rayed (rarely some simple), 0.4–0.8 mm. Cauline leaves: 10–30 (–45), often concealing stem proximally; blade auricles 2–5 (–6) mm, surfaces of distalmost leaves pubescent. Racemes 12–50 (–70) -flowered, usually unbranched. Fruiting pedicels usually divaricate-ascending, rarely horizontal, gently recurved or straight, 8–22 mm, pubescent, trichomes subappressed, 2–4-rayed. Flowers ascending at anthesis; sepals pubescent; petals purple, 9–14 × 2–4 mm, glabrous or sparsely pubescent (trichomes abaxially); pollen ellipsoid. Fruits usually divaricate-ascending, rarely horizontal, not appressed to rachis, not secund, usually curved, edges parallel, (6–) 8–13 cm × 1.5–2.2 mm; valves glabrous or trichomes relatively few, scattered; ovules 90–250 per ovary; style 0.01–0.5 mm. Seeds uniseriate or sub-biseriate, 1.5–1.7 × 1–1.2 mm; wing continuous, 0.1–0.2 mm wide.


Phenology: Flowering Mar–Jun.
Habitat: Rocky hillsides and cliffs in pine forests and chaparral
Elevation: 300-1800 m

Discussion

Although usually treated as a variety of Arabis (Boechera) sparsiflora (e.g., R. C. Rollins 1993), B. arcuata is easily distinguished from that species by having rachises and fruiting pedicels pubescent with subappressed, 2–4-rayed trichomes and a geographic range limited to southern and western California. By contrast, B. sparsiflora has rachises and fruiting pedicels with spreading, usually simple trichomes (sometimes glabrescent) and an allopatric distribution north and east of the Sierra Nevada.

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 arcuata"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Nuttall) Windham & Al-Shehbaz +
not +  and rosulate +
Streptanthus arcuatus +
appendaged +  and unappendaged +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
linear;oblanceolate +
much smaller +  and reduced +
2mm;7mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
6 cm60 mm <br />0.06 m <br /> (8 cm80 mm <br />0.08 m <br />) +
8 cm80 mm <br />0.08 m <br /> (13 cm130 mm <br />0.13 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
300-1800 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
horizontal +  and divaricate-ascending +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky hillsides and cliffs in pine forests and chaparral +
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 (?) +
0.9 cm9 mm <br />0.009 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
rudimentary +
pubescent +  and glabrous +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Flowering Mar–Jun. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
Harvard Pap. Bot. +
unbranched;12-50(-70)-flowered +
elongated +
reflexed +, ascending +  and erect +
slender +
mucilaginous +
margined +, not winged +  and winged +
sub-biseriate +  and uniseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.17 cm1.7 mm <br />0.0017 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 +
0.001 cm0.01 mm <br />1.0e-5 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
Arabis holboellii var. arcuata +, Arabis maxima +  and Arabis sparsiflora var. arcuata +
Boechera arcuata +
Boechera +
species +
short-stalked +  and simple +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
perennial +  and long-lived +
recurved +, horizontal +  and divaricate-ascending +
0.8 cm8 mm <br />0.008 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.1mm;0.2mm +