Primary thallus: squamulose, persistent; squamules: 2-4 x 1-3 mm, subentire to lobed podetia: 5-35 mm tall, ashy white to glaucescent green, cup-forming; cups: 4-10 mm wide, with long (up to 2 cm), slender, branching and anastomosing proliferations from margins surface: mostly smoothly corticate, esorediate, or in part verruculose or squamulose Apothecia: rare, at tips of proliferations, 0.3-3.2 mm diam, dark brown ascospores: oblong to fusiform, 10-16 x 4-5 micro meter Pycnidia: common, on cup margins, pyriform, constricted at base, short-stalked, with hyaline gelatin conidia: 3-8 x 0.5-1micro meter Spot tests: K-, C-, KC-, P+ red, UV- Secondary metabolite: fumarprotocetraric acid. World distribution: western North America and the West Indies Sonoran distribution: southern California (Santa Barbara Co.). Notes: Cladonia dimorpha is similar in habit to C. pyxidata, but the cup margins produce long, fissured proliferations that are similar to those of C. furcata. When the proliferations are not developed (in juvenile podetia), the species are difficult to separate. However, in the Sonoran region the ranges of the two species probably do not overlap.