Hamadryads (Ἁμαδρυάδες, Αμαδρυάδες) are Greek mythological beings that live in trees. They are a specific species of dryad, which are a particular type of nymph. Hamadryads are born bonded to a specific tree. If their tree died, the hamadryad associated with it died as well. For that reason, dryads and the gods punished any mortals who harmed trees.
Pan and Hamadryad, Pompeii
A Hamadryad, John William Waterhouse (1917).
Hamadryad also is another name for the King Cobra.