The sword in the stone. Contrary to common belief, this sword was not actually Excalibur. King Arthur recieved Excalibur from The Lady of the Lake later on after the sword in the stone had actually broken.
A dryad is a tree nymph, that is a female spirit of a tree, in Greek mythology. In Greek drys signifies "oak". Thus dryads are specifically the nymphs of oak trees, though the term has come to be used for all tree nymphs in general. They were normally considered to be very shy creatures, except around the goddess Artemis, who was known to be a friend to most nymphs.