Boechera xylopoda

Windham & Al-Shehbaz

Harvard Pap. Bot. 12: 250. 2007.

Basionym: Arabis pulchra var. gracilis M. E. Jones Contr. W. Bot. 8: 41. 1898
Synonyms: Arabis pulchra var. glabrescens Wiggins Arabis pulchra var. viridis Jepson Boechera pulchra var. gracilis (M. E. Jones) Dorn
Treatment appears in FNA Volume 7. Treatment on page 411. Mentioned on page 354, 375, 400, 412.

Perennials; long-lived; apomictic; caudex woody. Stems usually 1 from per caudex branch, arising from center of leaf tuft, elevated above ground surface on woody base, (3–) 5–7.5 dm, pubescent proximally, trichomes short-stalked, 2–5-rayed, 0.25–0.9 mm., similarly pubescent distally. Basal leaves: blade linear-oblanceolate to oblanceolate, 3–7 mm wide, margins entire or somewhat dentate, ciliate near petiole base, trichomes (simple), to 1.5 mm, surfaces densely pubescent, trichomes short-stalked, 4–8-rayed, 0.15–0.5 mm. Cauline leaves: 8–18, usually not concealing stem; blade auricles 1–2 mm, surfaces of distalmost leaves sparsely pubescent. Racemes 20–38-flowered, usually unbranched. Fruiting pedicels descending-divaricate, usually recurved, 9–20 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. Flowers divaricate to pendent at anthesis; sepals pubescent; petals purple, 9–12 × 2–3.5 mm, sparsely pubescent (often some trichomes abaxially); pollen spheroid. Fruits reflexed, not appressed to rachis, not secund, straight, edges parallel, 5–7 cm × 2–2.5 mm; valves glabrous proximally, sparsely pubescent distally; ovules 98–126 per ovary; style 0.1–0.5 mm. Seeds sub-biseriate, 2–2.5 × 1.3–1.6 mm; wing continuous, 0.2–0.25 mm wide.


Phenology: Flowering Mar–May.
Habitat: Rock outcrops and gravelly slopes, often under shelter of shrubs in desert scrub, sagebrush, and chaparral communities
Elevation: 900-2000 m

Discussion

Although usually treated as a variety of Arabis (Boechera) pulchra, B. xylopoda is an apomictic taxon that is morphologically intermediate between B. perennans and B. pulchra (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison) and probably arose through hybridization between those two sexual diploids.

Arabis trichopoda Greene (1908), not Turczaninow (1840) is an illegitimate name, sometimes found in synonymy with Boechera xylopoda.

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 xylopoda"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
Windham & Al-Shehbaz +
not +  and rosulate +
Arabis pulchra var. gracilis +
appendaged +  and unappendaged +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
linear-oblanceolate;oblanceolate +
much smaller +  and reduced +
3mm;7mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Calif. +  and Nev. +
5 cm50 mm <br />0.05 m <br /> (7 cm70 mm <br />0.07 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
900-2000 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
straight +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rock outcrops and gravelly slopes, often under shelter of shrubs in desert scrub, sagebrush, and chaparral communities +
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 +
Magenta (?) +, Red (?) +, Yellowish (?) +, Purple (?) +, Lavender (?) +, Pink (?) +  and White (?) +
0.9 cm9 mm <br />0.009 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
rudimentary +
0.2 cm2 mm <br />0.002 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
Flowering Mar–May. +
trinucleate +  and 3(-11)-colpate +
spheroid +
Harvard Pap. Bot. +
unbranched;20-38-flowered +
elongated +
reflexed +, ascending +  and erect +
slender +
mucilaginous +
margined +, not winged +  and winged +
sub-biseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
orbicular +, oblong +  and flattened +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.16 cm1.6 mm <br />0.0016 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 +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
Arabis pulchra var. glabrescens +, Arabis pulchra var. viridis +  and Boechera pulchra var. gracilis +
Boechera xylopoda +
Boechera +
species +
branched +  and short-stalked +
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
pubescent +  and glabrous +
anastomosing +
descending-divaricate +
perennial +  and long-lived +
glabrous +  and pubescent +
0.9 cm9 mm <br />0.009 m <br /> (2 cm20 mm <br />0.02 m <br />) +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.2mm;0.25mm +