9. Eriogonum pelinophilum Reveal, Great Basin Naturalist 33: 120. 1973 • Clay-loving wild buckwheat
Plant low, heavily branched subshrubs, 0.5-1(-1.2) × 0.8-3(-4) dm, floccose to glabrous and grayish. Leaves basally cauline, solitary; leaf-blades oblanceolate, 0.5-1.2(-1.5) × 0.01-0.2(-0.3) cm, densely white-tomentose abaxially, subglabrous to glabrous and green adaxially, tightly revolute; petioles 0.05-0.1 cm. Flowering stems numerous, erect to spreading, 0.05-0.1 dm. Inflorescences cymose, compact, 0.01-0.2 × 0.1-0.3 dm; bracts 3, scalelike, 0.5-1 mm, triangular. Peduncles, when present, erect, 0.1-0.5 cm, floccose to glabrous. Involucres solitary, narrowly turbinate, 2.5-3.5 × 1-1.5 mm, floccose to glabrous; teeth 5, erect, 0.3-0.4 mm. Flowers cream, (2.5-)3-3.5 mm, glabrous; perianth lobes essentially monomorphic, oblong, 0.8-1.2 mm wide, united 1/2 their length. Stamens slightly exserted, 2.5-4 mm; filaments sparsely pilose basally. Achenes trigonous, light brown, 3-3.5 mm, glabrous.
Flowering spring-summer spring-summer (May-Jul). Heavy clay flats and slopes in saltbush communities; 1600-1900 m; wc Colo. - see map (yellow boxes are extant populations; red crosses are populations presumed to be extirpated).Eriogonum pelinophilum is known only from Delta and Montrose counties, Colorado. It is related to E. clavellatum and both species occur on Mancos shale. The two are well-separated geographically. Eriogonum pelinophilum is a smaller plant than E. clavellatum in habit. The perianth lobes of E. clavellatum are distinctly dimorphic with those of the outer whorl fan-shaped and about twice the width of those of the inner whorl. In E. pelinophilum the lobes are essentially similar, with those of the outer whorl no more than a third broader. Much of the former habitat occupied by E. pelinophilum has been destroyed in the Montrose, Colorado, area since the species was listed as endangered in 1984. A small population is preserved at the Fairview Natural Area east of Montrose. Ants actively pollinate the flowers, being involved with both self- and cross-pollination. Some 50 additional visitors were found associated with the flowers, but none was confirmed as a pollinator.
County Listings:
COLORADO: Delta and Montrose.
Eriogonum pelinophilum Reveal - habit in full flower
Eriogonum pelinophilum Reveal - habit in early flower
Eriogonum pelinophilum Reveal - habit showing exposed caudex system
Eriogonum pelinophilum Reveal - branching pattern
Eriogonum pelinophilum Reveal - leaves
Eriogonum pelinophilum Reveal - inflorescences
Eriogonum pelinophilum Reveal - inflorescences
Eriogonum pelinophilum Reveal - detail of the inflorescences
Eriogonum pelinophilum Reveal - involucres and flowers
Eriogonum pelinophilum Reveal - details of involucres and flowers
Eriogonum pelinophilum Reveal - details of involucres and flowers
Eriogonum pelinophilum Reveal - flowers
All images copyrighted and may be used only with permission - contact James L. Reveal. Webpage published by the University of Maryland
