The importance of regeneration to plant habitat specialization has been poorly studied. ten Brink et al. examine the adaptive association between germination ecology and specialization to either forest or open habitats in a comparative experiment using 17 congeneric species pairs with contrasting habitat preference. They find that seeds of forest and open habitat species respond differently to environmental cues. In a conceptual model they show that species from the two habitats are adapted to utilize different windows of opportunity in time (season) and space (habitat), and they suggest that phases in the plant life cycle other than the established phase should be considered important in adaptive specialization.