Biological Species in Pleurotus
RONALD H. PETERSEN, KAREN W. HUGHES, AND NADEZHDA PSURTSEVA
Introduction and purpose
In naming our Pleurotus We just can't seem to win. Sapidus is out, pulmonarius is in. What to call the mountain ones and those in Denver town? Populinus is up, pulmonarius is down. And species ostreatus,the name we thought the best? Tis only in the east: pulmonarius grows out west. What happens to this genus With decurrent gills galore? Why, it's not even an agaric, Now it's a polypore. This taxonomic slight-of-hand we find all but incredible. Oh well, at least for now our oysters are still edible.
"Lament of a Colorado mushroomer" Jerry Lavelle, In: Mycophile 38 (6):8
The lament above concerns the plight of mycophagists to name the commonly collected edible "oyster mushroom" basidiomata, but it applies equally to professional mycologists who persist in publishing papers in which Pleurotus names are used without any confidence that such usage is correct. For example, the names Pleurotus sapidus and P. sajor-caju are still used in research literature even though both are incorrect for different reasons. As indicated by Vilgalys et al. (1996) and Petersen (1995), it would appear that the most fastidious separation of taxa is by compatibility tests, and that the results dictate identifying "intersterility groups" (ISGs of Vilgalys) or "biological species" (of Petersen). Following similar work in Armillaria, Vilgalys et al. (1993) numbered Pleurotus ISGs.
Equally important to the purpose of this outline is a statement of what this outline is not. It is a brief summary of historical developments in work on the genus, including techniques used to elucidate systematics in the group, and a summary of the biological species presently known and understood. It is not a compilation of literature on: 1) edibility, growth for fruiting whether commercial or cabin-craft; 2) biochemistry or medicinal uses; 3) floristic works in which the putative species are listed for some geographical region; or 4) a source of synonymous names although they are mentioned when important. It is intended for the researcher, not the mycophagist, although it is hoped that the mycophagist might glean some interesting information. It will not relieve the angst which caused the poetic lines above.
This document is accompanied by deposition of a battery of tester strains of Pleurotus taxa in the Centraalbureau voor Schimmelcultures, Baarn, the Netherlands, whence they will be available in perpetuity. This battery should make possible the compatibility experiments necessary to securely tie research strains to names. The guidelines for such a battery (Petersen, 1995) have been followed.
Material has been arranged in an introduction to the ideas and techniques available for work in Pleurotus systematics, followed by an outline of the biological species now known, and finally by some names requiring further research before reaching biological species status.