Great Basin Naturalist 27: 114, fig. 1. 1967.
Herbs, matted, not scapose, 0.3–1 × 1–2 dm, glabrous, green. Stems spreading, usually with persistent leaf bases, up to 1/5 height of plant; caudex stems matted; aerial flowering stems mostly erect, slender, solid, not fistulose, 0.03–0.1 dm, glabrous or floccose or sparsely tomentose. Leaves basal, 1 per node but congested; petiole 0.5–1 cm, tomentose to floccose or glabrous; blade linear to linear-oblanceolate, (2–)3–6 × 0.1–0.3 cm, densely white-tomentose abaxially, less so or glabrous and green adaxially, margins revolute. Inflorescences cymose-umbellate, 1.5–3 × 1.5–3 cm; branches dichotomous, glabrous; bracts 3, semileaflike, usually triangular, 3–5 mm. Peduncles stout, 0.1–0.4 cm, glabrous. Involucres 1 per node, turbinate-campanulate, 2.5–3.5(–4.5) × 2–3 mm, glabrous except for cottony tomentum between teeth; teeth 5, erect, 0.3–0.5 mm. Flowers 2–3.5 mm; perianth white, glabrous; tepals connate proximal 1/4–1/3, monomorphic, oblanceolate to elliptic; stamens exserted, 3–4 mm; filaments sparsely pilose proximally. Achenes brown, 2.5–3.5 mm, glabrous.
Phenology: Flowering Jun–Sep.
Habitat: Clay hills and flats or granitic sandy slopes, mixed grassland and sagebrush communities
Elevation: 2200-2600 m
Eriogonum exilifolium is known only from Grand, Jackson, and Larimer counties, Colorado, and from Carbon and Albany counties, Wyoming. The drop-leaf wild buckwheat is a “species of concern” in Wyoming.