Two new species of Myxomycetes from a tropical deciduous forest of Mexico

Two new myxomycete species recorded from the semiarid lands of the Neotropi cs are described. Crihraria fragilis sp. nov. is distinguished from all oth er species of the genus by its unique spores, which have smooth bands arran ged in longitudinal arcs, and by the minute sporocarps each with a deep cal yculus and without a peridial net. Diderma acanthosporum sp. nov. has a uni que combination of characters; these are a pseudoaethalioid fructification with stalked sporocarps and depressed sporothecae, a calcareous, crustose e xternal peridial layer, and large spores, paler on one side and with long s pines. Comments on the distribution and ecology of these two species are in cluded.