MATING SYSTEMS OF 3 MEADOW PLANT-SPECIES

The area of species-rich hay meadows in Norway has been drastically reduced during the 20th century. This continuing process results in fragmentation and isolation of remaining habitats. Small and isolated populations may have reduced gene flow. This is a crucial factor for the structure and cohesiveness of populations. Gene flow in plant species is regulated by pollen and seed dispersal, and pollen dispersal is controlled by the species' mating system. As part of a research project on habitat fragmentation three meadow species (Dactylorhiza sambucina, Hypochoeris maculata, Polygala vulgaris) with different life strategies were therefore selected for studies of their mating systems. A hand pollination experiment showed that both Dactylorhiza sambucina and Polygala vulgaris were self-compatible. Seed set in H. maculata was low and the species may be considered as pseudo-self-compatible or self-incompatible. Using Bawa's (1974) criteria, however, also Hypochoeris maculata should be considered as self-compatible. All three species enhanced outbreeding but P. vulgaris also proved to be a good selfer and autogamous.