The Dryad riding school

Trees have long been thought to house spirits. Dryads are such spirits, members of the lesser deities known as nymphs in Greek mythology. They exist to watch over and  care for the tree in which they are born. Dryads are always female and so how they come to be born in the first place is a bit of a mystery!
Apparently Dryads enjoy horse riding and it is not uncommon to find their saddles among the trees. Those of a less romantic nature think that Dryad's saddles are a polypore bracket fungus known as Polyporus squamosus.