Building the jigsaw puzzle of the critically endangered Pleurotus nebrodensis: historical collection sites and an emended description

Historical collection sites of the critically endangered Pleurotus nebrodensis were retraced in Sicily (southern Italy) using recently rediscovered documents and through interviews with local people. These localities were visited in 2009 and checked for the presence of this rare mushroom, confirming a continuing decline in fruiting. An emended description of the taxon is provided based on observations on abundant recently collected material. The need for more incisive action to safeguard this valuable mushroom by the University of Palermo, Regional Park of Madonie Administration and policy makers is emphasized.