Dioecious. Plants 0.5-4 cm. Stolons none. Basal leaves: 1-nerved, linear to narrowly spatulate, 8-11 × 1-1.2 mm, tips acute, faces ± gray-tomentose. Cauline leaves linear or oblanceolate, 7-12 mm, not flagged (apices acute). Heads borne singly. Involucres: staminate 6-8 mm; pistillate 10-11 mm. Phyllaries distally dingy brown (apices acute-acuminate). Corollas: staminate 3-5 mm; pistillate 8-10 mm. Cypselae 2-3.5 mm, pubescent; pappi: staminate 4.5-6 mm; pistillate 10-12 mm. 2n = 28, 56.

Flowering early-mid spring. Sagebrush steppe, plains, foothills of mountains; 600-3400 m; Alta., B.C., Sask.; Calif., Colo., Idaho, Mont., Nebr., Nev., N.Mex., Oreg., Utah, Wash., Wyo.

Antennaria dimorpha is characterized by narrowly oblanceolate leaves and relatively large heads (borne singly). It is, perhaps, the most xerophytic of spring-blooming Antennaria species. It belongs to the Dimorphae group.