Boechera perennans

(S. Watson) W. A. Weber

Phytologia 51: 370. 1982.

Basionym: Arabis perennans S. Watson Proc. Amer. Acad. Arts 22: 467. 1887
Synonyms: Arabis angulata Greene ex Wooton & Standley Arabis arcuata var. perennans (S. Watson) M. E. Jones Arabis eremophila Greene Arabis recondita Greene
Treatment appears in FNA Volume 7. Treatment on page 396. Mentioned on page 359, 360, 375, 377, 381, 383, 398, 411, 412.

Perennials; long-lived; sexual; caudex woody. Stems usually 2–5 per caudex branch, arising laterally proximal to sterile shoots or rosette, often elevated above ground surface on woody base, (1.5–) 2–7 dm, densely pubescent proximally, trichomes short-stalked, Y-shaped, 0.2–0.4 mm, often mixed with 3–5-rayed or (rarely) simple ones, usually glabrous distally. Basal leaves: blade oblanceolate to obovate, 3–15 (–20) mm wide, margins dentate, ciliate proximally, trichomes to 1.2 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 3–6-rayed, 0.2–0.4 mm. Cauline leaves: 4–12 (–17), not concealing stem; blade auricles 0.5–3.5 mm, surfaces of distalmost leaves glabrous. Racemes 16–35-flowered, usually unbranched. Fruiting pedicels usually horizontal, straight or slightly recurved, (6–) 10–25 mm, usually glabrous. Flowers ascending at anthesis; sepals pubescent; petals white to purplish, 5–9 × 1–1.5 mm, glabrous or sparsely pubescent (occasionally some trichomes abaxially); pollen ellipsoid. Fruits widely pendent, not appressed to rachis, not secund, usually curved, edges parallel, (3–) 4–7 cm × 1.7–2.1 mm; valves glabrous; ovules 60–96 per ovary; style 0.05–0.4 mm. Seeds uniseriate, 1.1–1.5 × 0.9–1.2 mm; wing continuous, 0.1–0.2 mm wide. 2n = 14.


Phenology: Flowering Feb–May.
Habitat: Rocky slopes and gravelly soil in warm desert, chaparral, low montane habitats
Elevation: 200-1700 m

Distribution

V7 566-distribution-map.gif

Ariz., Calif., Nev., N.Mex., Tex., Utah, Mexico (Baja California), Mexico (Chihuahua), Mexico (Sonora)

Discussion

The circumscription of Boechera perennans followed here is much narrower than that adopted by R. C. Rollins (1993). The most significant difference is the removal of Arabis gracilenta. Recent studies (M. D. Windham and Allphin, in prep.) indicate that the latter represents an older name for the species usually called A. (Boechera) selbyi. Although superficially similar, B. perennans is distinguished from B. gracilenta by having stems arising from above ground surface on woody bases, proximal stems with mostly Y-shaped trichomes, strongly dentate margins on basal leaves, and uniseriate seeds. Typically, B. perennans is a sexual diploid largely restricted to the warm deserts of Arizona, California, Nevada, and southern New Mexico. Plants of B. gracilenta are scattered across the Colorado Plateau (northeast of the range of B. perennans) and are apomictic triploids, apparently produced by hybridization between B. fendleri and B. pallidifolia.

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 perennans"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(S. Watson) W. A. Weber +
not +  and rosulate +
Arabis perennans +
appendaged +  and unappendaged +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate;obovate +
much smaller +  and reduced +
3mm;15mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Ariz. +, Calif. +, Nev. +, N.Mex. +, Tex. +, Utah +, Mexico (Baja California) +, Mexico (Chihuahua) +  and Mexico (Sonora) +
3 cm30 mm <br />0.03 m <br /> (4 cm40 mm <br />0.04 m <br />) +
4 cm40 mm <br />0.04 m <br /> (7 cm70 mm <br />0.07 m <br />) +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.21 cm2.1 mm <br />0.0021 m <br />) +
200-1700 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky slopes and gravelly soil in warm desert, chaparral, low montane habitats +
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 +
0.5 cm5 mm <br />0.005 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
rudimentary +
pubescent +  and glabrous +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Flowering Feb–May. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
unbranched;16-35-flowered +
0.6 cm6 mm <br />0.006 m <br /> (1 cm10 mm <br />0.01 m <br />) +
elongated +
recurved +  and horizontal +
slender +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 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 /> (0.15 cm1.5 mm <br />0.0015 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 +
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 />) +
glabrous +  and pubescent +
Arabis angulata +, Arabis arcuata var. perennans +, Arabis eremophila +  and Arabis recondita +
Boechera perennans +
Boechera +
species +
y--shaped +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
perennial +  and long-lived +
hispid +, hirsute +, pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.1mm;0.2mm +