Popularly grown and versatile in the kitchen, oyster mushrooms  can also be found growing in the wild throughout the year, particularily when the night temperatures dip near zero.  around here, I usually find them around the winter solstice and through the winter and early spring.  Oysters prefer growing on hardwood, particularly beech and sycamore, have white lamellae which turn yellow brown in age, and caps that vary from almost black to blue grey to brown, tan, and almost white. .