Callistosporium is a genus of fungi in the order Agaricales. Basidiocarps (fruit bodies) are agarics (gilled mushrooms), either with a central stipe (stalk) or pleurotoid (with a lateral stipe). The latter group were formerly referred to Pleurocollybia. Recent molecular research, based on cladistic analysis of DNA sequences, has shown that the genus is a natural, monophyletic grouping, though not all species have yet been sequenced. Species are saprotrophic, typically growing on wood, and the genus is found worldwide.