Four species of Collybia sensu late are reported from the Hawaiian Islands:
Rhodocollybia laulaha and Gymnopus menehune represent new species, while G
. luxurains and G. subpruinosus are first reports. All four Hawaiian taxa a
re fully described, illustrated and compared with allied taxa. Marasmius su
bpruinosus, M. subcyathiformis and Clitocybe collybioides are formally tran
sferred to Gymnopus. An artificial dichotomous key to Hawaiian Rhodocollybi
a and Gymnopus is presented.