Abstract
An interesting species of lepiotaceous fungi, Leucoagaricus callainitinctus sp. nov., is described from Kerala State, India based on morphology and molecular phylogeny. This species is distinguished by basidiocarps that turn dark turquoise on bruising/handling or reacting with NH4OH. A phylogenetic study was conducted based on Maximum likelihood analysis of nrITS sequences. In the phylogram, the new species nested as a distinct lineage in a group, which consisted predominantly of members of section Piloselli of the genus Leucoagaricus. A comprehensive description, photographs of the basidiocarps and the microscopic structures, comparisons with phenetically similar and phylogenetically related species and a phylogram showing the placement of the new species are provided.