Ultrastructure of Licea kleistobolus (Myxomycetes) and its bearing on the taxonomic affinity of the species

The peridium of Licea kleistobolus Martin consists of two distinct layers. Abundant refuse matter is evenly distributed on the surface of the fructification. The upper surface of the operculum is smooth and punctated by pores of variable size. The internal structure of the operculum is essentially the same as that of the peridium. Processes along the periphery of the lower surface of the operculum and along the upper edge of the sporangium function as an opening mechanism. The operculum bears hollow finger-like outgrowths and rounded warts, both being continuous with the inner wall of the operculum. The results of a SEM- and TEM-study indicate that the two different types of processes are homologous structures. Similarity between aberrant cap-illitial outgrowths along the margin of lobes in Listerella paradoxa Jahn and the processes bordering the sporangial edge and periphery of the operculum in L. kleistobolus , indicates affinity of the two species.