Biological Species in Pleurotus
INTERSTERILITY GROUP
ISG VIII. Pleurotus levis (Berkeley and Curtis) Singer
1951. Lilloa 22: 271. 1951. Lilloa 22: 271.
Nomenclatural history: Berkeley and Curtis (1853) proposed Panus levis, which Singer recombined into Pleurotus. Pegler (1983) used the epithet as Lentinus levis (Berk. & Curt.) Murrill (1915)
Typification (teste Pegler, 1982: holotype): UNITED STATES, South Carolina, VII., coll. Ravenel no. 808 (Curtis 2949), herb. Berkeley (K).
Taxonomic history: In the field, basidiomata are usually milk white, centrally stipitate, and with no sign of a partial veil. The pileus surface can be velutinous to strigose, and occasional basidiomata are pastel pink. Separation from P. dryinus is difficult, but P. levis seems to be a summer fungus (and subtropical to tropical), while P. dryinus is a fall to early winter fungus more common in northwest United States and adjacent Canada. European records of P. dryinus abound, but P. levis is not reliably known.
Culture characteristics: Some cultures produce microdroplets typical of Pleurotus while others do not. Basidiomata produced in vitro exhibit a fugacious partial veil, and often turn banana yellow in age. No evidence of pinkish tints have been observed in in vitro basidiomata.
Genetic isolation history: Petersen (unpubl. data) has found that P. levis and P. dryinus are incompatible, although morphological characters are similar.
Mating system: tetrapolar.
Self-cross: United States, Commonw. Puerto Rico, rt. 128., 27.V.92, coll. RHP & S. Cantrell, Tennessee tracking number 4478 (TENN 50971). Tester Strains: 4478:11 = A1B1; 4478:14 = A2B2; 4478:7 = A1B2; 4478:10 = A2B1.
Anamorphic state: unknown.