Gaea the Elder God, former mother of Thor? Or Gaia the alien matter-creating/reshaping immortal mutant?
In either case, when where they part of the Academy X era? I don't really recall Nature Girl being around yet. (Dryad was the maybe-plant-controller, who never really got a chance to show off her stuff, although her father was said to be a famous mutant gardener who designed the hedge maze used in a school challenge.)