Boechera pusilla

(Rollins) Dorn

Vasc. Pl. Wyoming ed. 3, 376. 2001.

Basionym: Arabis pusilla Rollins Contr. Gray Herb. 212: 107. 1982
Treatment appears in FNA Volume 7. Treatment on page 400. Mentioned on page 352, 353, 356, 359, 363.

Perennials; long-lived; (cespitose); apomictic; caudex often woody. Stems usually 2–6 per caudex branch, arising from margin of rosette near ground surface, 0.5–2 dm, glabrous or sparsely pubescent proximally, trichomes simple and short-stalked, 2-rayed, to 0.2 mm, glabrous distally. Basal leaves: blade linear-oblanceolate, 1–2.5 mm wide, margins entire, ciliate along petiole, trichomes (simple), 0.4–0.7 mm, surfaces usually sparsely pubescent, rarely glabrous, trichomes short-stalked, 2-rayed or 3-rayed, 0.1–0.4 mm. Cauline leaves: 3–5, not concealing stem; blade auricles 0–0.2 mm, surfaces of distalmost leaves usually glabrous or, rarely, margins sparsely ciliate. Racemes 6–13-flowered, unbranched. Fruiting pedicels horizontal to divaricate-descending, straight or slightly curved downward, 2–5 mm, glabrous. Flowers divaricate-ascending at anthesis; sepals glabrous or sparsely pubescent, trichomes spreading, 2-rayed; petals white to lavender, 4–5 × 1.5–1.8 mm, glabrous; pollen spheroid. Fruits horizontal or divaricate-descending, not appressed to rachis, secund, straight, edges parallel, 1.6–3.2 cm × 1.5–2 mm; valves glabrous; ovules 20–32 per ovary; style 0.1–0.4 mm. Seeds uniseriate, 1.2–1.5 × 0.8–0.9 mm; not winged or with distal wing 0.05–0.1 mm wide.


Phenology: Flowering May–Jun.
Habitat: Cracks and crevices of granitic rock outcrops
Elevation: 2400-2500 m

Discussion

Of conservation concern.

Morphological evidence suggests that Boechera pusilla is an apomictic species that arose through hybridization between B. lemmonii and B. pendulina; it is known only from the type locality in southwestern Wyoming.

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 pusilla"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Rollins) Dorn +
not +  and rosulate +
Arabis pusilla +
appendaged +  and unappendaged +
0 cm0 mm <br />0 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
not +  and auriculate +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
linear-oblanceolate +
much smaller +  and reduced +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.01 cm0.1 mm <br />1.0e-4 m <br />) +
1.6 cm16 mm <br />0.016 m <br /> (3.2 cm32 mm <br />0.032 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
2400-2500 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
divaricate-ascending +
straight +
divaricate-descending +  and horizontal +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Cracks and crevices of granitic rock outcrops +
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 +
white +  and lavender +
rudimentary +
oblanceolate +  and spatulate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
Flowering May–Jun. +
trinucleate +  and 3(-11)-colpate +
spheroid +
Vasc. Pl. Wyoming ed. +
unbranched;6-13-flowered +
curved +  and straight +
downward +, horizontal +  and divaricate-descending +
slender +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
mucilaginous +
with distal wing +  and not winged +
biseriate +, sub-biseriate +  and uniseriate +
not +  and mucilaginous +
white +, black +, brown +  and yellow +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
orbicular +, oblong +  and flattened +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.01 cm0.1 mm <br />1.0e-4 m <br />) +
persistent +  and caducous +
distinct +
spreading +, ascending +  and erect +
pubescent +  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 +
pubescent +  and glabrous +
2 +  and 6 +
subsessile +, sessile +  and petiolate +
persistent +
distinct +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
, +, glabrous +  and pubescent +
Cruciferae +
Boechera pusilla +
Boechera +
species +
short-stalked +  and simple +
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 +  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 +