SUMMARYUsing two dimorphic species with diallelic incompatibility. Primula farinosa \^. 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 numher, tnight, contrary to most fitness models, select for plants which set relatively few seeds.In P. farinosa we discovered positive relationships between seed number per eapsule and capsule nutiiber per inflorescence. As capsules are formed in most flowers, scapes with tew flowers set the fewest seeds per capsule. This suggests that conspieuousness to pollinators and/or plant resource play an important role in reproductive success in this species. Seed size and seedling performance were also positively associated.For P. farinosa, which has multi-seeded fruits, we discovered an inverse association between seed size and seed tiumher for capsules containing more than 65 seeds. We suggest that stabilizing selection may occur for flower number per inflorescence in this species, as inflorescences with 8-11 capsules tend to set many seeds which tnay be inefficiently small. This tends to confSrm our hypothesis.However, for A. maritima there is a positive association between seed size and seed number per inflorescence. For such plants with single-seeded fruits there should be directional selection for large flower number per inflorescence, a trend which may have led to the evolution of the capitulum.

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