When walking in broad-leaved woodlands, especially where horse chestnut or sycamore trees are present, you may encounter the large capped bracket fungus usually known as dryad's saddle but more specifically called the scaly polypore (Polyporus squamosus); squamosus means scaly. A dryad, by the way, is a tree nymph in Greek mythology.
When I say large I mean large, the cap can be as much as two feet across! Dryad's Saddle is big and impressive. It is a yellowish-green colour when fresh becoming brown and black with age. It is widespread and quite common and emerges in spring. It is parasitic and any tree with it has no chance of survival.
It is supposedly edible when young but who would want to cut such a wonderful fungus from its home just to eat it?