Phylogenetic analyses and the distribution of nematophagy support a monophyletic Pleurotaceae within the polyphyletic pleurotoid-lentinoid fungi

Phylogenetic analyses based on partial sequences from nuclear 25S rDNA indi cate a mono-phyletic Pleurotaceae, consisting of the monophyletic genera Pl eurotus and Hohenbuehelia, within the poly-phletic pleurotoid-lentinoid fun gi. The attack and consumption of nematodes (nematophagy) supports the mono phyly of this family. Other pleurotoid-lentinoid fungi that have been studi ed are not nematophagous and, in phylogenetic analyses, occur within the eu agaric, polyporoid and russuloid clades. The pleurotoid agarics Lampteromyc es, Lentinula, Nothopanus, and Omphalotus form a clade together with Gymnop us dryophilus. A clade that corresponds to the Tricholomataceae includes th e pleurotoid agarics Conchomyces, Hypsizygus, Phyllotopsis, and Resupinatus . Faerberia, Heliocybe, Lentinus, Neolentinus, and Panus are gilled polypor es, and all deserve recognition at the generic level. The brown-rotters Hel iocybe and Neolentinus form a distinct clade within the polypores together with the brown-rotting polypore, Gloeophyllum. The Pleurotaceae belong in t he Agaricales, are not closely related to or synonymous with the Polyporace ae, and should be restricted to the genera Pleurotus and Hohenbuehelia. An isolate of Hohenbuehelia from Alberta, Canada produces adhesive knobs typic al of Hohenbuehelia and its anamorph Nematoctonus, and also nonadhesive nem atotoxic droplets characteristic of Pleurotus. This combination is unique w ithin Hohenbuehelia and Pleurotus. Phylogenetic genetic analyses place this species at the base of the genus Hohenbuehelia, indicating that nematotoxi c droplets were probably present in the common ancestor of Pleurotus and Ho henbuehelia. In contrast, the gelatinized fruiting bodies of Hohenbuehelia and Resupinatus are independently derived. The tribe Resupinateae (Tricholo mataceae) should be restricted to Resupinatus (including Asterotus) and cyp helloid allies such as Stigmatolemma.