Didymium anellus

Didymium anellus Morgan, Jour. Cine. Soc. Nat
Hist. 16: 148. 1894.
Didymium effusum var. tenue Lister, Jour. Bot. 35: 214. 1897.
Plasmodiocarps often forming small rings, or elongate, simple or branching and netted, 0.3-0.5 mm. wide, varying to flattened, pulvinate sporangiate fruitings, these rarely shortstalked, or to broad, crustose, pitted plasmodiocarps; peridium membranous, colorless or purplish-brown, iridescent, covered with a rather sparse layer of lime crystals; dehiscence mainly circumscissile ; columella none or represented by n brown deposit at the base of the sporangium; capillitium abundant, of branching and anastomosing, slender, purple threads forming a somewhat elastic net; hypothallus thin, delicate, often scarcely apparent; spores dark brown in mass, violaceous-brown by transmitted light, minutely war ted, usually with clusters of larger warts, 7.5-11 p in diameter.
Type locality: Ohio.
Habitat: Dead leaves, herbaceous stems and twigs, rarely on wood.
Distribution: New York through southern Canada to Washington, south to Pennsylvania, New Mexico, and California; Europe; Asia.