Eriogonum capillare (Not NMRPTC Rare)
[taxon report][distribution map][all photos][line drawing]
(San Carlos wild buckwheat)
Scientific Name: Eriogonum capillare Small
Vernacular Name: San Carlos wild buckwheat
R-E-D Code: 1-1-2
Description: Annual, 2-4 dm tall; leaves basal, obovate to rounded, 1-3 cm long and wide, sparsely villous to hirsute and green on both surfaces, margins entire, petioles 1-3 cm long; stems erect, 5-15 cm long, glabrous and glaucous; inflorescence open to dense, cymose paniculate, the branches 1-3 dm long, spreading, trichotomously branched at the first node, dichotomously branched above, the ultimate branches often slender; peduncles slender, 1-3 cm long; flowers in small involucrate clusters, glabrous; tepals pandurate (fiddle-shaped with a constriction in the middle), white with green or reddish midribs and bases, 0.8-1.2 mm long; achenes brown to black, 1.3-1.6 mm long. Flowers July to October.
Similar Species: There are several annual species of Eriogonum in southwestern New Mexico. Eriogonum capillare is distinguished by the following combination of characteristics: leaves all basal, sparsely pubescent (not woolly); flowers glabrous, not yellow; tepals constricted in the middle like a fiddle.
Distribution: New Mexico, Hidalgo County; southeastern Arizona.
Habitat: Rocky andesitic soils in Chihuahuan desert scrub; 1,350 m (4,450 ft) at the New Mexico location.
Remarks: The study by Reichenbacher, Schmalzel, and Bainbridge (1993) in Arizona brought the number of specimen collections in that state up to 64 with most of these representing different localities. The range of Eriogonum capillare is about 120 miles east to west and about 100 miles north to south, which means this species occupies most of southeastern Arizona. The range and abundance of this species are too great to qualify as rare under NMRPTC criteria.
Conservation Considerations: This species is not seriously threatened by the prevailing land uses within its habitats.
Important Literature (*Illustration):
Reichenbacher, F.W., R.J. Schmalzel and S.J. Bainbridge. 1993. San Carlos wild buckwheat (Eriogonum capillare) status report. Unpublished report prepared for U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, Phoenix, Arizona. 30 pp.
Reveal, J.L. 1976. Eriogonum (Polygonaceae) of Arizona and New Mexico. Phytologia 34(5):409-484.
Information Compiled By:
Ken Heil, Joey Herring, 1999; last updated 2006