Herbs, erect, annual, (2-)4-18(-22) dm, glabrous, bright green. Stems: caudex absent; aerial flowering stems erect, hollow and fistulose, 0.5-3.5(-5) dm, glabrous, minutely glandular proximally, infrequently also short-hispid. Leaves basal; petiole 1-6 cm, hirsute; blade round to reniform, (0.5-)1-2.5(-4) × (0.5-)1-2(-3) cm, short-hirsute on both surfaces and greenish, margins plane. Inflorescences cymose, open, spreading to erect, 30-150(-170) × 10-80 cm; branches usually fistulose, glabrous; bracts 3, scalelike, 1-4 × 1-2 mm. Peduncles mostly spreading, straight, slightly bent distally, capillary, 1-4 cm, glabrous. Involucres turbinate, 1-1.5(-1.8) × 0.6-0.9(-1.2) mm, glabrous; teeth 4, erect, 0.3-0.5 mm. Flowers 1.5-2.5 mm; perianth yellow with greenish to reddish midribs, densely hirsute with coarse curved hairs; tepals monomorphic, narrowly ovate; stamens exserted, 0.9-1.5 mm; filaments glabrous or sparsely pubescent proximally. Achenes light brown to brown, 3-gonous, 2-2.5 mm, glabrous. 2n = 32. Flowering year-round. Clayey flats and slopes, mixed grassland, chaparral, saltbush, and sagebrush commun-ities, oak and montane conifer woodlands; 400-1100 m; Calif., Nev.; Mexico (Baja California). Eriogonum clavatum is the tall, slender member of the E. inflatum complex found on the Inner Coast, Peninsular, and Transverse ranges of southern California. It is rather common from Monterey and San Benito counties southward to Ventura, northwestern Los Angeles, and extreme southwestern Kern counties, and then disjunct in the Peninsular Ranges of Riverside and San Diego counties, where it just enters north-central Baja California, Mexico. It extends eastward onto desert ranges, where it rarely exceeds 6 dm in height, from southern Mono County and Inyo County south through western San Bernardino County to northwestern Riverside County. From Inyo County, the species occurs across southern Nye and northern Clark counties into western Lincoln County, Nevada.