Slender wild buckwheat

Eriogonum microtheca var. idahoense (Rydberg) S. Stokes

Shrubs, (2.5-)3-5 × 3-7 dm. Stems: caudex absent; aerial flowering stems 0.3-0.7 dm, floccose or glabrous. Leaves: blade oblanceolate to elliptic, (0.8-)1-2(-2.7) × (0.3-)0.4-0.9(-1.2) cm, densely white-tomentose abaxially, floccose or glabrous adaxially, margins not revolute. Inflorescences 3-10 cm; branches floccose or glabrous. Involucres 2.5-3 mm, floccose or glabrous. Flowers 2-2.5 mm; perianth yellow. Achenes 2-2.5 mm.

Flowering Jul-Sep. Gravelly to rocky slopes, saltbush and sagebrush communities, juniper and conifer woodlands; 600-1100 m; Idaho, Oreg.

Variety microtheca is found in the foothills and low mountains north of the Intermountain Region in Baker, Crook, Grant, Malheur, Sherman, Wasco, and Wheeler counties in Oregon. Scattered populations also occur in Washington County, Idaho. The variety is disjunct onto the Pueblo Mountains of Harney County, Oregon.