A new species and a new section of the genus Mycena from the Netherlands

Mycena cecidiophila is newly described and illustrated. It grows on knopper galls on the cups of Quercus robur, and was collected from a single site in the Netherlands, Huys ten Donck estate. Although the new species resembles a species of sect. Sacchariferae, it differs in the negative Melzer-reaction on the lamella trama. The new section Cecidiophilae is therefore proposed here to accommodate the new species, characterized by warty elements of the pileipellis, amyloid spores, and absence of pleuro- and cheilocystidia.