Melanoleuca melaleuca

About

Melanoleuca melaleuca is a species of mushroom in the family Tricholomataceae, and it is the type species of its genus Melanoleuca. It is difficult to distinguish from other related species firstly because it is variable, secondly because the taxonomic criteria are often based on characteristics which have later been found to be variable, and thirdly because there is much disagreement between authorities as to an exact species definition.

Summary from Wikipedia