Array
Draba standleyi
(Standley's whitlowgrass)
[taxon report][distribution map][photos][line drawing]
Family: Brassicaceae
Scientific Name: Draba standleyi J.F. Macbride & Payson
Synonyms: Draba chrysantha S. Watson var. gilgiana (Wooton & Standley) O.E. Schulz; Draba gilgiana Wooton & Standley 1913, not Muschler 1906
Vernacular Name: Standley's whitlowgrass
R-E-D Code: 2-1-2
Description: Tufted perennial; caudex simple or closely branched, thick with marcescent (withered but persistent) leaf bases; stems few, 1-3 dm long, very slender, erect to partially decumbent, simple or few-branched, sparsely pubescent below with simple or forked trichomes, glabrous above or glabrous throughout; basal leaves narrowly oblanceolate, long-petioled, entire or remotely denticulate, pubescent to merely ciliate with stiff appressed hairs or glabrous, 1.5-8 cm long, stem leaves 1-8, small, remote, sessile but not auriculate, few-toothed or entire; inflorescences much elongated, 5- to 20-flowered; petals 4, yellow; fruiting pedicels erect to divaricately ascending, 8-13 mm long; siliques linear-elliptic to oblong, glabrous or nearly so, flat or contorted, 8-12 mm long; styles 1-2 mm long. Flowers June to August.
Similar Species: Draba standleyi is apparently most similar to D. petrophila, which is endemic to southeastern Arizona and adjacent northern Sonora (and perhaps southwestern New Mexico). It has also been confused with D. mogollonica, which can be distinguished by the characteristics in the table below. Both D. standleyi and D. petrophila are perennials with marcescent leaf bases. Both also have relatively long leaves and long styles in fruit. However, in D. standleyi the trichomes of the leaves and stems are simple or wanting and the stem leaves are few and remote, whereas in D. petrophila the trichomes of the leaves and stems are mostly cruciform to dendritic and the stem leaves are several and usually overlapping.
|
Draba |
LONGEVITY |
CROWN/STEM |
STEM TRICHOMES |
BASAL LEAVES |
CAULINE LEAVES |
FRUITING PEDICELS |
STYLES |
|
mogollonica |
annual/ biennial |
tap rooted; no marcescent leaf bases |
simple below; glabrous above |
flat rosette; 4-9 cm long |
1-3, reduced |
widely spreading, 1-2 cm long |
1-2.25 mm |
|
petrophila |
perennial |
marcescent leaf bases; stems relatively stout |
cruciform to dendritic |
numerous; 3-8 cm long |
3-30, usually overlapping |
4-12 mm |
1.5-3 mm |
|
standleyi |
perennial |
marcescent leaf bases; stems very slender |
simple or forked & glabrous above or all glabrous |
tufted; 1.5-8 cm long |
1-8, reduced, remote |
erect to divaricately spreading, 8-13 mm |
1-2 mm |
Distribution: New Mexico, Doņa Ana (Organ Mountains), Otero, Sierra, and Socorro counties; Texas, Jeff Davis County, Davis Mountains; southern Arizona; Mexico, northwestern Coahuila.
Habitat: Igneous rock faces, bases of overhanging cliffs, clefts of porphyritic and andesitic rocks and soil; 1,675-1,980 m (5,500-6,500 ft).
Remarks: The known populations are widely disjunct. However, its habitat, volcanic cliffs, is not particularly rare in the region and the plant may be more common than presently understood.
Conservation Considerations: This plant grows in habitats that have few disturbances.
Important Literature (*Illustration):
MacBride, J.F. and E.B. Payson. 1918. Annals of the Missouri Botanical Garden 5:150.
Rollins, R.C. 1993. The Cruciferae of continental North America. Stanford University Press, Stanford, California.
Wooton, E.O. and P.C. Standley. 1913. Descriptions of new plants preliminary to a report upon the flora of New Mexico. Contributions from the U.S. National Herbarium 16(4):124. [type description, as Draba gilgiana]
Information Compiled By: David Bleakly, 1999
Agency Status:
