Smooth arrow-leaf wild buckwheat

Eriogonum compositum var. simplex (S. Watson ex Piper) H. St. John & F. A. Warren

Plants 2-4(-5) dm. Aerial flowering stems usually slender, infrequently fistulose, 1-3 dm, usually glabrous, rarely floccose. Leaf blades ovate to deltoid, 3-10(-15) × 2-4(-4.5) cm. Involucres glabrous or more commonly weakly glandular-puberulent. Flowers 5-6 mm; perianth usually bright yellow.

Flowering May-Jul. Sandy to gravelly slopes, mixed grassland and sagebrush communities, oak and montane conifer woodlands; 30-1600(-2000) m; Idaho, Oreg., Wash.

Variety leianthum is mostly occasional to locally common in eastern Washington, northwestern and west-central Idaho, and northeastern Oregon.