Primary thallus: squamulose, persistent; squamules: 1-5 mm long, 0.5-3.5 mm wide, gray, pruinose (occasionally strongly pruinose), with occasional granules and phyllidia on upper surface; margin: crenulate to lobulate; underside: white, softly cottony, occasionally slightly veined toward base, sometimes sorediate along the margins, dying base not blackened podetia: whitish-gray, 4-15 mm tall, 1-2 mm wide, simple, straight to curved, sturdy, subulate to obtuse when young but soon forming narrow cups; cups: 1-2.8 mm wide, shallow, inner surface phyllidiate, occasionally split but generally without marginal proliferations surface: totally ecorticate or corticated basally (up to 1 mm high), sorediate with distinct farinose soredia (0.1-0.2 mm diam), usually mixed with spherical, corticate granules (0.2-0.5 mm wide), with phyllidia, microsquamules or (at base) macrosquamules giving the surface a rough appearance (although podetial tips remaining farinose); medulla: white, exposed in places, Apothecia: rare, sometimes compound; disc: up to 2 mm wide, dark brown ascospores: not observed Pycnidia: rare, borne on cup margins, spherical, brown, sessile or slightly stalked, 0.5 mm wide, ascogonial primordia also brown conidia: not observed Spot tests: K+ reddish-brown, C-, KC-, P+ red, UV- Secondary metabolites: fumarprotocetraric acid and trace amounts of protocetraric and confumarprotocetraric acids, occasionally with traces of convirensic acid or unknown secondary products. Habitat and ecology: primarily on bare mineral soil on road banks and crevices of rock outcrops, but also on rotten wood, mainly in forested areas from 60 to 3000 m World distribution: North America (central Mexico to SW USA) Sonoran distribution: Arizona, southern California, Baja California and Chihuahua. Notes: Cladonia subfimbriata has often been identified as C. fimbriata because of its simple, sorediate podetia. It differs from C. fimbriata by producing subulate podetia at a young stage, having narrow cups and podetia (that therefore appear elongated). The soredia of C. subfimbriata are also rougher. Cladonia subfimbriata may actually be closer to C. subulata, as it resembles that species in surface structure and color. However, C. subfimbriata is smaller, unbranched, and commonly produces narrow cups, which do not bear proliferations. Young and short morphotypes of C. subulata may be difficult to distinguish from this species. The widespread occurrence of C. subfimbriata in Mexico in areas where C. subulata is absent confirms that the two species are distinct. More field work is required to define the limits between C. subfimbriata, C. fimbriata, and C. subulata.