Trematosphaeria

**Semantic type:** Fungus

**Definition:** A genus of mostly saprobic or hemibiotrophic fungi in the phylum Ascomycota with additional species inhabiting marine and freshwater environments. Species in this genus are characterized by medium to large sized ascomata with peridia composed of small compressed cells, clavate to cylindrical bitunicate asci, a trabeculate hamathecium in a gelatinous matrix and reddish-brown ellipsoid to fusoid transversely septate ascospores sometimes with paler end cells.