Primary thallus: squamulose, persistent or evanescent; squamules: 1-3 x 1-2 mm, soft, fragile, convex to imbricate, fluffy below but sometimes granular or sorediate podetia: 1-3 (-4.5) cm tall, 0.3-1 (-1.5) mm wide, grayish green, producing cups (rarely subulate); cups: 3-7 (-15) mm wide; margins: entire to dentate, thin, erect or slightly recurved surface: ecorticate or at base corticate, finely to coarsely sorediate, also with minute isidioid phyllidia and with globose, corticate granules or microsquamules; soredial layer: thinning and revealing grooved, white to brownish stereome Apothecia: rather common, 1-5 mm wide, light to dark brown, on long (4-7 mm) stalks ascospores: fusiform, 8.5-12.5 x 2-3.5 micro meter pycnidia: infrequent, semiglobose to pyriform, with hyaline gelatin conidia: not observed Spot tests: K-, C-, KC-, P+ red, UV- Secondary metabolites: fumarprotocetraric acid and accessory convirensic acid. Habitat and ecology: on rotting wood , tree bases and earth banks, in tropical and subtropical habitats World distribution: Africa, Asia, Australasia, North America and South America Sonoran distribution: Chihuahua and Sinaloa. Notes: Cladonia subsquamosa is a widespread, tropical counterpart of C. chlorophaea and was recently recognized as distinct (e.g., Ahti 2000). It is common in Mexico south of the study area and also extends to Florida. It contrast, C. fimbriata produces a persistent, thick cover of farinose soredia (although the stalk of the podetium is sometimes corticate). In C. subsquamosa the soredia are more loosely attached, even become isidioid, and easily disintegrate; its outer medulla is very thin and is not conspicuously white. This species is distinguished from C. chlorophaea by having sorediate podetia that lack a distinct cortex on its stalks. Chemically C. subsquamosa differs by constantly producing rather high amounts of convirensic acid, which is scarce or absent in the other species. The name of the present species should not be confused with the much used C. subsquamosa (Nyl. ex Vain.) Cromb., which is a synonym of C. squamosa (see above).