Draba cusickii

B. L. Robinson ex O. E. Schulz in H. G. A. Engler

in H. G. A. Engler, Pflanzenr. 89[IV,105]: 105. 1927.

Endemic
Synonyms: Draba sphaeroides var. cusickii (B. L. Robinson ex O. E. Schulz) C. L. Hitchcock
Treatment appears in FNA Volume 7. Treatment on page 304. Mentioned on page 284, 305, 329, 342.

Perennials; (loosely cespitose); caudex branched (with few, persistent leaf remains); scapose. Stems unbranched, 0.3–1.2 dm, pubescent throughout, trichomes (2–) 4-rayed, 0.05–0.5 (–0.6) mm. Basal leaves rosulate; shortly petiolate; petiole base ciliate (margin not ciliate, trichomes 2-rayed, 0.3–0.6 mm); blade oblanceolate to obovate, 0.4–1.2 cm × 2–5 mm, margins entire or, rarely, denticulate, surfaces pubescent with stalked, (2–) 4-rayed trichomes, 0.15–0.4 mm. Cauline leaves 0. Racemes 10–20 (–25) -flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stems proximally. Fruiting pedicels divaricate-ascending, straight (not expanded basally), 4–9 mm, pubescent, trichomes (2–) 4-rayed, (0.05–0.25 mm). Flowers: sepals broadly ovate, 2–2.5 mm, pubescent, (trichomes short-stalked, 3-rayed or 4-rayed); petals yellow, obovate to oblanceolate, 3.7–6 × 1.5–2.5 mm; anthers ovate, 0.5–0.6 mm. Fruits lanceolate to broadly ovate, plane, flattened, 6–9 × 2–4.5 mm; valves pubescent, trichomes short-stalked, (2–) 4-rayed, 0.05–0.25 mm; ovules 10–18 per ovary; style 0.4 0.8 (–1) mm. Seeds oblong, 1.2–1.5 × 0.7–0.8 mm. 2n = 26.


Phenology: Flowering Jun–Jul.
Habitat: Basaltic outcrops, talus, rocky soil
Elevation: 2000-2700 m

Discussion

Draba cusickii was divided by R. C. Rollins (1993) into two varieties with significantly different morphologies and chromosome numbers. The Nevada endemic var. pedicellata (2n = 20) is here treated as a distinct species following M. D. Windham (2004). Draba cusickii has the same chromosome number as D. sobolifera but is readily distinguished from that species by having 4-rayed (versus simple or 2-rayed) fruit trichomes. Draba cusickii is known from Steens Mountain (Harney County).

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 "Draba cusickii"
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
Ihsan A. Al-Shehbaz +, Michael D. Windham +  and Reidar Elven +
B. L. Robinson ex O. E. Schulz in H. G. A. Engler +
appendaged +  and unappendaged +
not +  and auriculate +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
lobed +, toothed +  and entire +
oblanceolate;obovate +
much smaller +  and reduced +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
urceolate +, campanulate +  and tubular +
scapose +  and branched +
sessile +  and petiolate +
well-developed +
distinct +
well-differentiated +
emarginate +  and entire +
2000-2700 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
not basally +  and dilated +
actinomorphic +
orange;purple;orange;purple;pink;white;yellow +
spreading +, ascending +  and erect +
linear +, oblanceolate +, spatulate +, obovate +, subsaccate +, not saccate +, oblong +  and ovate +
latiseptate +, twisted +  and sessile +
indehiscent +  and dehiscent +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
flattened +, plane +, lanceolate +  and broadly ovate +
0.2 cm2 mm <br />0.002 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
Basaltic outcrops, talus, rocky soil +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
denticulate +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
3.7mm;6mm +
rudimentary +
obovate +  and oblanceolate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Flowering Jun–Jul. +
trinucleate +  and 3(-11)-colpate +
in H. G. A. Engler, Pflanzenr. +
ebracteate;10-20(-25)-flowered +
ascending +  and erect +
slender +
not flexuous +
mucilaginous +
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 />) +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
persistent +  and caducous +
distinct +
spreading +, ascending +  and erect +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
reduced +
latiseptate +, twisted +  and sessile +
indehiscent +  and dehiscent +
terete +, plane +, subglobose +, ovoid +, suborbicular +, linear +, oblong +, elliptic +, lanceolate +  and ovate +
latiseptate +, twisted +  and sessile +
indehiscent +  and dehiscent +
terete +, plane +, subglobose +, ovoid +, suborbicular +, linear +, oblong +, elliptic +, lanceolate +  and ovate +
tetradynamous +
procumbent +  and decumbent +
prostrate +  and decumbent +
usually erect +  and ascending +
subsessile +, sessile +  and petiolate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
persistent +
distinct +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
Draba sphaeroides var. cusickii +
Draba cusickii +
species +
short-stalked +  and stalked +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
cruciform +  and forked +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.025 cm0.25 mm <br />2.5e-4 m <br />) +
coiled +, 1-7-veined +  and veined +
anastomosing +
scapose +  and not +
divaricate-ascending +
0.4 cm4 mm <br />0.004 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +