The genus Acytostelium

Members of the genus Acytostelium are the smallest Dictyostelids, character ized by slender acellular sorophores which support very small globose to su bglobose sori. Seven species are presented as new; all were isolated since 1990, and all but one from ecologically diverse tropical environments. They are: A. digitatum, from semievergreen rain forest at Tikal, Guatemala; A. aggregatum and A. amazonicum, from tropical rain forest of the Peruvian Ama zon; A. pendulum, from a Mayan milpa in Southern Belize; the largest, A. ma gnuphorum, from a bog in North Central Ohio; A. reticulatum, from the lower montane zone of the Loquillo Experimental Forest, Puerto Rico, and the sma llest, A. minutissimum, from elfin woodland on the rim of Volcan Cacao in C osta Rica.