Biological Species in Pleurotus
INTERSTERILITY GROUP
ISG XVI: Pleurotus calyptratus (Lindb. apud Fries) Saccardo.
1887. Syll. Fung. 5: 341.. 1887. Syll. Fung. 5: 341.
Photo by I. Krisai-Greilhuber
Nomenclatural history: Fries (1857) attributed the epithet to Lindblad, proposing the combination as Agaricus calyptratus. According to Fries, there is an illustration of this species at present-day Institute of Botany, Stockholm. Fries (1874) persisted in this combination. Saccardo recombined the epithet in Pleurotus.
Typification (type not designated; viz. Fries, 1857): SWEDEN, Sudermannland, Högholms, on Populus tremula.
Taxonomic history: The presence of a partial veil obscures placement of this species, and Singer accordingly transferred the epithet to Tectella, also diagnosed by such a veil. Tectella patellaris (type species of the genus), however, produces a distinct gelatinized layer in the pileus trama and is pseudostipitate. Tectella patellaris has been included in Panellus by some authors. Cultures of P. calyptratus produce nematostatic microdroplets, confirming its placement in Pleurotus. Stipe tissue is dimitic, indicating placement with P. djamor and others with such flesh construction.
Genetic isolation history: Although usually cited as a discrete morphological taxon based on the well-developed partial veil on the pleurotoid basidiome, Dr. Rytas Vilgalys (pers. comm.; and see Zervakis, 1998) has found that occasional monokaryons of P. calyptratus are intercompatible with monokaryons of P. djamor. No hybrid basidiomata have been produced, however, so the occasional intercompatibility is not accompanied by interfertility. We have confirmed low levels of intercompatibility between these taxa using different strains. By traditional standards, the two taxa may be interpreted as closely related, since their sexual recognition system is similar enough to produce "hybrid" dikaryons.
Mating system: tetrapolar.
Self-cross: AUSTRIA,Vienna, Danube Riverine Forest, 5.IV.97, coll. I. Krisai-Greilhuber, Tennessee tracking number 9065 (TENN 57451). Tester strains: 9065:28 = A1B1; 9065:5 = A2B2; 9065:2 = A2B1; A1B2 not represented.