Ultrastructure of Asci and ascospore appendages in Linocarpon appendiculatum and L-nipae

The fine structure of the asci and ascospore appendages of Linocarpon appen diculatum and L. nipae is reported. The ascus wall in both species comprise d a single electron-dense granular layer. The apical ring in L. appendicula tum comprised a C-shaped electron-dense structure, and this is compared wit h similar pyrenomycetes. The ascospore wall of both species comprised a thi n episporium and a thick bipartite mesosporium, and the basal appendages co mprised a fibrillar component. The appendicular fibrils in L. appendiculatu m were surrounded by a collar-like structure, which was absent in L. nipae.