Some sample questions from this category:
* These sisters were transformed into alder trees -- which stand at river-sides weeping amber 'tears' -- by their own father, to assuage the grief they felt at the death of their brother. Who were they?
* This daughter of Nereus and priestess of Artemis was transformed (by the goddess or by her father, depending on the version of the myth) into a spring, to save her from the unwanted attentions of the river-god Alpheus.
* This nymph was ravished by Hades and then transformed by him into a white poplar tree. Who was she?
* I fled from Apollo when he fell in love with me. My father, a river god, changed me into a laurel tree. Who am I?
* I fled from Pan, the son of Hermes. I was changed into reeds, which could be cut and made into a set of pipes. Who am I?