Seed weight and seed number affect subsequent fitness in outcrossing and selfing Primula species.

Using the outcrossing Primula farinosa and its autogamous selfing relatives P. scotica, P. scandinavica and P.

Fitness constraints on flower number, seed number and seed size in the dimorphic species Primula farinosa L. and Armeria maritima (Miller) Willd.

Using two dimorphic species with diallelic incompatibility, Primula farinosa L. and Armeria maritima (Miller) Willd., we tested the hypothesis that an association of seedling performance with seed size, and an inverse association of seed size with seed number, might, contrary to most fitness models, select for plants which set relatively few seeds.