Leaf blades usually ovate (lanceolate, ovate, very widely ovate, or reniform). Internodes of secondary branches subtending involucres in fruit usually well defined and not crowded. Flowering spring-fall (Apr-Oct). Primary and disturbed vegetation, desert shrub, mesa slopes, disturbed grounds, roadsides, in gypseous limestone, rocky, gravelly alluvial and limestone soils; 600-1500 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Durango).