Biological Species in Pleurotus
RONALD H. PETERSEN, KAREN W. HUGHES, AND NADEZHDA PSURTSEVA
Historic Taxonomy
The venerable Nees von Esenbeck (1816: 194, 197) envisioned that Agaricus (only lately taken to represent gilled, stipitate mushrooms instead of polypores) was divisable into a number of units. One of these was diagnosed by basidiomata on wood, eccentrically to laterally stipitate (or without a discernable stipe). Members of such a morphological group he informally placed in Pleuropus, Crepidotus, Apus, Resupinatus, etc. Persoon (1801: 472) appreciated this division and called a portion of it Pleuropus.
Fries (1821:9) sorted mushrooms by their spore color (in spore prints), so the various laterally stipitate groups were segregated in several directions. The catch-all genus for gilled mushrooms was Agaricus, and one series was Leucosporus. The white-spored, laterally stipitate basidiomata were designated as Tribus XII. Pleurotus. This name was not adopted at genus rank, but as an infrageneric level only. Within the tribe were elements of several present-day genera: Pleurotus, Hypsizygus, Lentinus, Hohenbuehelia, Pleurocybella, and Lentinellus.
Although several generic names were proposed which impinged on Fries’s tribe, the core of the group was left intact through the years, but Quélet (1872) finally adopted the name Pleurotus at genus rank, with the core species accepted by Fries still within the genus.
As might be expected, when rules of nomenclature were imposed on the mycological community in 1867, and when the rule of typification was internationally accepted in 1935, fights broke out over what species would serve as the type for what genus. One such dealt with Pleurotus, but finally it was decided that the type species should be P. ostreatus (Jacquin: Fries) Kummer (1871).
In this way, the genus took shape and was refined into its present-day assemblage (viz, Miller 1986). As new taxonomic characters have been elucidated, diagnostic characters have been emphasized or withdrawn and others have emerged.