Herbs, erect or spreading, annual, 0.5-4(-5) dm, minutely viscid, yellowish green. Stems: caudex absent; aerial flowering stems erect, solid, not fistulose, 0.2-1 dm, minutely viscid. Leaves basal; petiole 0.5-4 cm, floccose; blade elliptic to broadly ovate, 0.5-3 × 0.5-3 cm, densely white-tomentose abaxially, thinly floccose to glabrate and greenish adaxially, margins plane. Inflorescences cymose, open, 3-35 × 3-30 cm; branches minutely viscid; bracts 3, scalelike, 1-2 × 1-2 mm. Peduncles erect or nearly so, straight, filiform, 0.5-1.5 cm, viscid. Involucres narrowly turbinate, 1-1.2 × 0.6-0.8 mm, viscid; teeth 4, erect, 0.3-0.5 mm. Flowers 1.3-1.5 mm in early anthesis, becoming 1.5-2 mm; perianth pale yellow to yellow in early anthesis, becoming tinged with red, glabrous; tepals monomorphic, oblong; stamens included, 0.9-1.1 mm; filaments glabrous. Achenes light to dark brown, 3-gonous, 0.8-1 mm, glabrous.
Flowering Apr-Jun. Sandy flats and slopes, saltbush and creosote bush communities; of conservation concern; 400-600 m; Ariz., Nev.
Eriogonum viscidulum is a rare and localized species known from a few locations in Clark County, Nevada, and adjacent Mohave County, Arizona. Its range extends from the Muddy River near Weiser Wash to the confluence with the Virgin River, and from Sandy Hollow Wash to Middle Point on the Colorado River. It is listed for protection by the state of Nevada and is considered a 'sensitive' species by the Bureau of Land Management and the Nevada Heritage Program. In Arizona, it is a 'special status species.'