A New Zealand Pleurotus with multiple-species sexual compatibility

A collection of Pleurotus pulmonarius from New Zealand (NZP) showed compatibility with four putatively separate biological species of Pleurotus (P. eryngii, P. ostreatus, P. populinus, P. pulmonarius) and with an undescribed member of the P. ostreatus complex (P. "abieticola"). Pairings of monokaryotic strains of P. pulmonarius with those of NZP were universally sexually compatible and produced stable, profilerating dikaryons. NZP compatibility with P. eryngii and P. populinus was partial, with a mixture of incompatible pairings, matings producing ephemeral dikaryons, and matings producing stable, proliferating dikaryons. Monokaryon pairings of NZP and P. ostreatus were either incompatible or produced ephemeral, unstable, non-proliferating dikaryons. In all cases, nuclear donation/migration was unilaterally into NZP. The mating system of NZP was tetrapolar although some features of the self-cross were atypical of the genus. Mating promiscuity by NZP with previously biologically defined taxa raises issues concerning the nature of separation of North American taxa.