Lophiostoma, Lophiotrema and Massarina are similar genera that are difficult to distinguish morphologically. In order to obtain a better understanding of these genera, lectotype material of the generic types, Lophiostoma macrostomun, Lophiotrema nucula and Massarina eburnea were examined and are re-described. The phylogeny of these genera is investigated based oil the analysis of 26 Lophiostoma- and Massarina-like taxa and three genes - 18S, 28S rDNA and RPB2. These taxa formed five well-supported sub-clades in Pleosporales. This Study confirms that both Lophiostoma and Massarina are polyphyletic. Massarina-like taxa can presently be differentiated into two groups - the Lentithecium group and the Massarina group. Of these, the type species M. eburnea together with the Massarina group represents Massarina sensu stricto. Lophiostoma taxa Clustered in two groups - one group, including the type species L. macrostomum, is characterized by fusiform, hyaline one-septate ascospores which are pigmented and 3-septate when senescent, clavate asci, and apical structures which are highly variable, being crest-like in L. macrostomum, all umbilicate pore surrounded by 4-6 radial ridges in L. rugulosum, or papillate in L. glabrotunicatum. The second group comprises Lophiostoma species with heavily pigmented multi-septate ascospores and compressed crests. Lophiotrema species including the type species L. nucula form a monophyletic group. One new genus - Lentithecium with five new species - Lentithecium aquaticum, Lophiostoma glabrotunicatum, L. rugulosum, Lophiotrema brunneosporum and L. lignicola and three new combinations - Lentithecium arundinaceum, L. fluviatile and L. lineare are introduced in this paper.