Three independent evolutionary events of sequestrate Lactifluus species in Australasia.

Abstract

Three Australian species with sequestrate basidiome forms are recorded for the first time in the genus Lactifluus based on nuclear ITS-LSU and morphological data. These species represent three rare independent evolutionary events resulting in sequestrate basidiomes arising from agaricoid species in three different sections in two subgenera. All three species have highly reduced basidiome forms, and no species with intermediate forms have been found. Lactifluus dendriticus is unique in the genus in having highly branched, dendritic terminal elements in the pileipellis. We provide full descriptions of two species: Zelleromyces dendriticus (= Lactifluus dendriticus comb. nov.) in Lactifluus subg. Lactifluus sect. Gerardii, and Lactifluus geoprofluens sp. nov. in Lf. subg. Lactifluus sect. Lactifluus. A reduced description is provided for the third, Lactifluus sp. prov. KV181 in Lf. subg. Pseudogymnocarpi sect. Pseudogymnocarpi, as it is currently known from a single sequence.