Supporting data for The fitness effects of outcrossing distance depend on parental flowering phenology in fragmented populations of a tallgrass prairie forb

The phenomena of isolation-by-distance and isolation-by-time shape mating patterns and population genetic processes, such as inbreeding and outbreeding depression, which influence progeny fitness. However, the effects of parental isolation in time on offspring fitness remain understudied, especially in combination with isolation-by-distance. We planted offspring from a common garden experiment involving 13 populations of the tallgrass prairie forb Echinacea angustifolia into a prairie restoration and tracked their fitness over 16 years. Parental source populations were up to 9 km apart, and flowering asynchronies spanned up to 13 days. Using Aster life-history analysis, we assessed how interparent distance and asynchrony affected offspring fitness. This dataset includes offspring fitness data (cumulative number of flowering heads produced), data on parental individuals, including source population proximity and asynchrony, and R code for the analysis. The data is being released in advance of publication of the associated study in New Phytologist.