Pleurotus dryinus

Pleurotus dryinus is a species of fungus in the family Pleurotaceae. It grows on dead wood and is also a weak pathogen; infecting especially broad-leaved trees. The species name is a Latinised version of the Greek word 'dryinos' (δρύῐνος), meaning 'related to oak', and referring to one of its main hosts. The original definition of this fungus as Agaricus dryinus was made by Persoon in 1800. In 1871 in his 'Führer in die Pilzkunde' ('Guide to mycology'), Paul Kummer introduced Pleurotus as a genus and defined three similar ringed species: Pleurotus corticatus, Pleurotus Albertini and P. dryinus. They were distinguished because only P. corticatus has intertwined ('anastomosing') gills on the stem and P. Albertini is bigger and grows on conifer wood rather than oak. However, nowadays all three are considered to be forms of the same species. The name dryinus takes precedence because it is the oldest. Also, in 1874 Fries defined a species Pleurotus tephrotrichus, having a deeper grey colour, which again has been incorporated into P. dryinus but may be distinguished as the variety P. dryinus var. tephrotrichus. The English name 'Veiled Oyster Mushroom' has been given to this species. The following sections use the given references throughout. This mushroom is saprobic on dead wood and can also be a weak parasite of trees. It occurs especially on oak (from which it derives its name), but also on beech, other broad-leaved trees, and occasionally on conifers. It is often solitary or may grow in small groups. Appearing from summer to autumn, it is distributed throughout Europe, where it varies locally between common and rare. It is also found in North America.