Boechera burkii

(Porter) Windham & Al-Shehbaz

Harvard Pap. Bot. 12: 237. 2007.

Basionym: Arabis laevigata var. burkii Porter Bull. Torrey Bot. Club 17: 15. 1890
Synonyms: Arabis burkii (Porter) Small
Treatment appears in FNA Volume 7. Treatment on page 368. Mentioned on page 351.

Biennials; short-lived; sexual; caudex not evident. Stems usually 1 per plant, arising from center of rosette near ground surface, (2–) 3–7 dm, glabrous throughout, often glaucous. Basal leaves: blade oblanceolate to obovate, 4–10 mm wide, margins dentate, not ciliate, surfaces glabrous or sparsely pubescent subapically, trichomes simple, 0.3–0.8 mm. Cauline leaves: 18–28, often concealing stem proximally; blade auricles absent, surfaces of distalmost leaves glabrous. Racemes 20–50-flowered, usually unbranched. Fruiting pedicels ascending to divaricate-ascending, usually straight, 4–12 mm, glabrous. Flowers ascending at anthesis; sepals glabrous; petals white, 3–5 × 0.5–0.7 mm, glabrous; pollen ellipsoid. Fruits divaricate-ascending, not appressed to rachis, not secund, usually curved, rarely straight, edges parallel, 5–10 cm × 1.5–1.8 mm; valves glabrous; ovules 64–80 per ovary; style 0.2–0.6 mm. Seeds uniseriate, 1.5–1.8 × 1.2–1.4 mm; wing continuous, 0.3–0.5 mm wide distally.


Phenology: Flowering Apr–May.
Habitat: Rocky areas, wooded slopes, stream banks

Distribution

V7 499-distribution-map.gif

Md., Pa., Tenn., Va., W.Va.

Discussion

Boechera burkii usually has been treated as a variety of Arabis laevigata (e.g., R. C. 1993). The two taxa differ substantially in leaf morphology, and no intermediates have been found despite broad overlap in their geographic ranges. Boechera burkii typically has 18–28 cauline leaves per plant, with blades linear, non-auriculate, and margins entire, whereas B. laevigata has 7–15 cauline leaves per plant, blades lanceolate, auriculate, and margins often dentate. The two are also separable on petal width, with B. burkii having significantly narrower petals (0.5–0.7 versus 1–1.5 mm wide).

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 burkii"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(Porter) Windham & Al-Shehbaz +
not +  and rosulate +
Arabis laevigata var. burkii +
appendaged +  and unappendaged +
lyrate-pinnatifid +, dentate +  and entire +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblanceolate;obovate +
much smaller +  and reduced +
4mm;10mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
not evident +
petiolate +  and sessile +
well-developed +
indistinct +
not +  and differentiated +
emarginate +  and entire +
Md. +, Pa. +, Tenn. +, Va. +  and W.Va. +
5 cm50 mm <br />0.05 m <br /> (10 cm100 mm <br />0.1 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
actinomorphic +
straight +  and curved +
divaricate-ascending +
torulose +, falcate +, lanceolate +, oblong +  and linear +
Rocky areas, wooded slopes, stream banks +
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 +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
rudimentary +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
Flowering Apr–May. +
trinucleate +  and 3(-11)-colpate +
ellipsoid +
Harvard Pap. Bot. +
unbranched;20-50-flowered +
elongated +
ascending +  and divaricate-ascending +
slender +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
mucilaginous +
margined +, not winged +  and winged +
biseriate +, sub-biseriate +  and uniseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
orbicular +, oblong +  and flattened +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.14 cm1.4 mm <br />0.0014 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 +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
glabrous +  and pubescent +
Arabis burkii +
Boechera burkii +
Boechera +
species +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
biennial +  and short-lived +
hispid +, hirsute +, pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +
0.3mm;0.5mm +