ULTRASTRUCTURE OF ASCOSPORES OF TUNICATISPORA-AUSTRALIENSIS

The ultrastructure of the ascospores of Tunicatispora australiensis is described. Mature ascospores possess three wall layers; an innermost tripartite mesosporium, a tripartite episporium and an outermost seven -laminate exosporium. Ascospores are characterized by a thick, irregul ar exosporium, and single-stranded, coiled episporial polar appendages which uncoil on contact with water. The nature of the spore appendage and exosporium are compared with those of other marine ascomycetes, a nd the taxonomic assignment of the species is discussed.