Sublittoral collection of fungal-infectedChondrus crispusover a 2-year period has allowed for a taxonomic reappraisal of the loculoascomyceteDidymosphaeria danica(Berlese) Wilson et Knoyle, an obligate parasite on the reproductive regions of host plants. A new genus,Lautitia, is proposed withLautitia danicacomb. nov. as the type species.Lautitia danicahas restrictedPleospora-typecentrum development; possesses septate pseudoparaphyses and hyaline, asymmetrically two-celled ascospores; and is placed in the Phaeosphaeriaceae, Pleosporales. In addition, the life historyof Lautitia danicais clarified.