Thallus: small to spreading, often over 2 cm in size, crustose, thin and membrane-like, sometimes ± lobate upper surface: blackish or dark olive green, smooth or rough and appearing coarsely granulose, often becoming irregularly plicate, dull lower surface: attached by rhizohyphae Apothecia: few to abundant, often lumped on thallus folds or lobe margins, immersed to semi-immersed, small, 0.2-0.3(-0.5) mm wide disc: at first small and punctiform, finally open, flat, yellowish or reddish brown, with thick, smooth, persisting thalline margin; proper exciple: thin, hyaline, IKI-; epihymenium: yellowish brown, K- hymenium: 100-130(-140) µm high, hyaline, IKI+ blue; subhymenium: hyaline, IKI+ blue ascus: 8-spored ascospores: simple, hyaline, ellipsoid to broad ellipsoid, (7.5-)10-17.5(-20) x 7.5-12.5(-15) µm, old ascospore walls up to 2.5(-5) µm thick Pycnidia: immersed, simple, hyaline, narrow-pyriform to ovoid conidia: hyaline, cylindrical, 23 x 1 µm Spot tests: all negative Secondary products: none detected. Substrate and ecology: on mosses over rock in somewhat sheltered situations World distribution: North America, Europe, Australia Sonoran distribution: central Arizona, and southern California. Notes: Lempholemma polyanthes is distinguished from Lempholemma chalazanum by its smaller ascospores and more spreading, often more rough and granulose, irregularly folded and plicate lobes. Among the exsiccate No. 812 distributed by H.E. Hasse as Collema chalazanum (=Lempholemma c.) a few samples apparently belong here.