THE REPRODUCTIVE-BIOLOGY OF THE MEDITERRANEAN ENDEMIC CYCLAMEN BALEARICUM WILLK (PRIMULACEAE)

Knowledge of the reproductive biology of endemic plants improves our u nderstanding of how mating system may be related to patterns of specie s abundance and provides a basis for the development of rational conse rvation programmes. In this paper we present natural population data o n the floral biology and reproductive ecology of the endemic Mediterra nean species Cyclamen balearicum Willk. This is a long-lived, diploid perennial herb which occurs in southern France in five fragmented and isolated regions and on the Balearic Islands of Mallorca, Menorca, Ibi za, Cabrera and Draponera. Our observations indicate a particularly sc arce pollinator activity (rare syrphid visits) and dispersal by ants o ver small distances. A controlled pollination experiment in a natural population showed that in southern France C. balearicum is fully self- compatible and that selfing is autonomous and probably delayed (i.e. f ollowing opportunities for outcrossing). The proximity of stigmas and anthers will favour autonomous selfing. The high pollen/ovule ratio in dicates nevertheless that C. balearicum has a mixed mating system. Pat terns of variation in stigma-anther separation and pollen production p er newer suggest that not only has the current mating system of the sp ecies evolved from an outcrossing ancestor but that due to the fragmen tation and isolation of populations greater levels of selfing have evo lved in southern France (and to an intermediate degree on Ibiza and Me norca). On the island of Mallorca where larger continuous belts of C. balearicum habitat still exist the species has floral traits indicatin g a more outcrossed mating system. To our knowledge this is the first paper to document such trends in floral traits in the endemic componen t of the Mediterranean flora. (C) 1995 The Linnean Society of London