Single-stem wild buckwheat

Eriogonum caespitosum Nuttall subsp. acaule (Nuttall) S. Stokes; E. caespitosum var. acaule (Nuttall) R. J. Davis

Herbs, matted, not scapose, 0.15-0.3 × 1-2 dm, tomentose, greenish. Stems matted, with persistent leaf bases, up to 8 height of plant; caudex stems matted; aerial flowering stems erect, slender, solid, not fistulose, 0.05-0.2 dm, tomentose. Leaves sheathing entire stem, 1 per node or fasciculate; petiole 0.05-0.15 cm, glabrous; blade linear to oblanceolate, 0.3-0.8 × 0.1-0.2 cm, densely white-tomentose on both surfaces, margins revolute.  Inflorescences cymose or racemose, condensed, 0.2-0.5(-0.8) × 0.3-0.8 cm; branches dichotomous or secondaries suppressed, tomentose; bracts absent. Peduncles absent. Involucres 1 per node, campanulate, 1.5-3 × 1.5-3 mm, tomentose; teeth 4-5, erect to slightly spreading, 1-2 mm. Flowers 2-2.5 mm; perianth yellow, white-tomentose abaxially; tepals connate proximal 1/4, monomorphic, lanceolate; stamens exserted, 2.5-3 mm; filaments pilose proximally. Achenes light brown, 2-2.5 mm, sparsely pubescent.

Flowering May-Jul. Gravelly or clayey flats and slopes, saltbush or sagebrush communities; 2000-2500 m; Colo., Wyo.

Eriogonum acaule is the ultimate reduction in the E. brevicaule complex. The low, matted habit of this rather elegant species makes it attractive to rock garden en-thusiasts. In Colorado, the Bureau of Land Management considers it a “sensitive” species; it is known only from Moffat County. It is encountered more frequently in Wyoming, where it is found in Albany, Carbon, Fremont, Lincoln, Natrona, Sublette, Sweetwater, Teton, and Uinta counties. The species is to be expected just south of the Daggett County line in northeastern Utah.