Marasmius sensu stricto in Peninsular Malaysia

A total of 43 species of Marasmius sensu stricto belonging to six sections (Globulares, Hygrometrici, Leveilleani, Marasmius, Neosessiles and Sicci) are reported from Peninsular Malaysia. Macro- and micromorphological characters in combination with ITS sequence data were used to circumscribe species. Of the 43 species reported herein, 9 represent new species, viz., M. angustilamellatus, M. diminutivus, M. distantifolius, M. iras, M. kanchingensis, M. kuthubutheenii, M. musicolor, M. ochropoides, and M. olivascens. An additional 19 species are new records for Peninsular Malaysia Phylogenetic analyses of 36 Malaysian Marasmius species were conducted based on sequence data from nrDNA ITS-1-5.8S-ITS-2 gene regions. The ITS data support the circumscription of species based on morphological characters and are useful in aiding species delimitations. The ITS data do not, however, support the current sectional delimitation of Marasmius wherein most sections are not monophyletic. Comprehensive descriptions, illustrations and photographs of each species, a key to aid in diagnosis, comparisons with allied species, and a preliminary phylogenetic construct are provided.