This crepidotus frequently plays tricks on people new to wild mushrooming. For a beginner, fresh specimens of Crepidotus applanatus, as long as they have not yet begun to drop their brown spores on top of a close neighbor, emerge from decomposing wood in irregular tiers. They kind of do look as if they might be Oyster Mushrooms in an immature stage of fruiting.
There are several differences in their overall size, attachment to wood, their texture, and their spore colors. It is in the Crepidotaceae family of the Agaricales order.
Crepidotus applanatus (Berk.) Sacc.
Crepidotus applanatus