Ultrastructural studies of Massarina ingoldiana and M. purpurascens

Ascus and ascospore appendage structures can be important characters in delineation of genera. We have therefore examined the ascus and ascospore ultrastructure of Massarina ingoldiana and M. purpurascens, as Massarina is thought to be a heterogeneous genus. The ascus wall of M. ingoldiana is two layered and comparable to M. thalassiae. Ascospores of both species comprise an electron-transparent mesosporium, an electron-dense episporium and an exosporial mucilaginous sheath. In this respect they are similar to the ultrastructure of other Massarina species, and should be maintained in Massarina.