Marasmiaceae

Marasmiaceae is a family of basidiomycete fungi in the order Agaricales. The family includes several genera, with Marasmius and Gymnopus being the most prominent. Members are generally small to medium-sized mushrooms with slender, tough stems and caps that are dry and often pale. A distinctive feature for many species is their ability to dry out and later rehydrate when moisture returns.

Spores are white to cream, and microscopic features vary among genera. The mushrooms are mostly saprotrophic, growing on leaf litter, wood, moss, or similar substrates in forests and grasslands. They are found worldwide, with higher diversity in temperate regions.

Taxonomy has shifted with molecular studies; several genera have been reassigned or redefined within or near the family. Notable genera include Marasmius, which contains species such as Marasmius oreades, the fairy-ring mushroom, and Gymnopus, which includes species formerly placed in Collybia.

In sum, the Marasmiaceae represent a cosmopolitan group of small, tough-tissued mushrooms united by common spore color and ecological habit, contributing to the decomposition of plant material in a range of habitats.