Breeding System Studies with Three Species of Anagallis(Primulaceae): Self-incompatibility and Reduced Female Fertility in A. monelli L.

The pollination biology, fruit set and breeding system of Anagallis arvensis, A. parviflora and A. monelli were studied in the field and glasshouse. No pollinators were observed at flowers of A. arvensis and A. parviflora , and hand pollinations indicated that these species are self-compatible taxa which automatically self-pollinate as the petals close at the end of the first day. Flowers of A. monelli were visited by several small halictid bee pollinators and a field diallel with seven plants indicated that this species is self-incompatible. Fruit set in A. monelli is correlated with distance to the nearest conspecific neighbour such that beyond 2 m fruit set is relatively low. The diallel cross, and also an analysis of the number of seeds per capsule for all plants located within 2 m of a conspecific, indicated that about 18% of the population of A. monelli showed low female fecundity and were thus ‘male dominant’ individuals.