Bull. Torrey Bot. Club 25: 51. 1898.
Herbs, erect, annual, (1–) 2–4 dm, glabrous. Stems: caudex absent; aerial flowering-stems erect, solid, not fistulose, 0.5–1.5 dm, glabrous. Leaves basal; petiole 1–3 cm, sparsely villous; blade obovate to round, 1–3 × 1–3 cm, sparsely villous to hirsute and greenish to grayish on both surfaces, margins plane. Inflorescences cymose, usually dense, 10–30 × 5–35 cm; branches not fistulose, glabrous; bracts 3, scalelike, 0.5–3 × 0.5–2.5 mm. Peduncles erect, straight, slender, 1–3 cm, glabrous. Involucres campanulate, 1–1.5 × 1–1.5 mm, glabrous; teeth 5, erect, 0.2–0.4 mm. Flowers 1–1.6 mm; perianth white with greenish or reddish midribs, becoming pink to rose, glabrous; tepals dimorphic, those of outer whorl pandurate with swollen, auriculate bases, those of inner whorl oblanceolate; stamens included to exserted, 0.8–1.2 mm; filaments glabrous. Achenes shiny brown to black, 3-gonous, 1.3–1.6 mm, glabrous.
Phenology: Flowering Sep–Oct.
Habitat: Sandy flats and washes, saltbush, greasewood, and mesquite communities
Elevation: 500-1500 m
Eriogonum capillare is known from southeastern Arizona (Gila, Graham, Greenlee, and Pima counties) and extreme southwestern New Mexico, where it is rare in northwestern Hidalgo County.
"dm" is not declared as a valid unit of measurement for this property.