Life history evolution, species differences, and phenotypic plasticity in hemiparasitic eyebrights (Euphrasia).

Phenotypic plasticity in response to host and environment confounds species delimitation in Euphrasia. When grown in a common garden environment, some morphologically distinct taxa can be identified, though others represent morphologically similar shallow segregates. Trait differences present between some species and populations demonstrate the rapid evolution of distinct life history strategies in response to local ecological conditions.