Perennials or subshrubs, to 30 cm; usually densely short-tomentose. Leaves (proximally opposite, distally alternate): petioles 3-10 mm; blades deltate, ovate, or suborbiculate, 5-15 × 5-15 mm, margins shallow-crenate to dentate. Heads borne singly or (2-10) in loose, corym-biform arrays, 7-9 × 6-9 mm. Peduncles 5-15 mm. Involucres campanulate to hemispheric. Phyllaries 15-20, oblanceolate to broadly lanceolate, 4-5 × 0.8-1.8 mm. Ray florets 0. Disc florets 20-45; corollas yellow, tubes 1-1.2 mm, throats tubular to narrowly funnelform, 1.3-1.6 mm, lobes 0.4-0.6 mm. Cypselae narrowly suboblong to oblanceolate, 2.5-3.5 mm, margins prominently calloused, short-hairy; pappi of 1(-2) stout bristles 1.8-2.8 mm. 2n = 34. Flowering spring-fall. Crevices of rocky canyon walls and cliff faces; of conservation concern; 800-1200 m; Ariz. Perityle ajoensis occurs in the Ajo Mountains of Organ Pipe Cactus National Monument in Pima County.