Three new ascomycetes from freshwater in China.

Three new freshwater ascomycetes, Diaporthe aquatica sp. nov. (Diaporthaceae), Ophioceras aquaticus sp. nov. (Magnaporthaceae) and Togninia aquatica sp. nov. (Togniniaceae), are described and illustrated based on morphological and molecular data (ITS, 18S, 28S rDNA sequences). Diaporthe aquatica is characterized by globose to subglobose, black ascomata with long necks, broadly cylindrical to obclavate asci, and small, ellipsoidal to fusiform, one-septate, hyaline ascospores; it is unusual among Diaporthe species in the fact that it lacks a stroma and has freshwater habitat. Ophioceras aquaticus is characterized by globose ascomata with a long beak, cylindrical, eight-spored asci with J- subapical rings and 3-5-septate filiform ascospores with slightly acute ends. Togninia aquatica is characterized by globose ascomata with long necks, clavate and truncate asci clustered on distinct ascogenous hyphae, and small, reniform, hyaline ascospores. Differences among the new taxa and similar species are discussed.