| The extent to which plants depend on pollinators for outcross pollen transportation is a key issue in plant reproductive ecology. We evaluated the putative breeding system, foral display, and natural pollination in two Southern Cone of South American orchids, Gavilea araucana and G. venosa, by performing four hand pollination trials (agamospermy, autogamy, geitonogamy, and xenogamy tests) and by counting each fower and fruit produced by plants in natural conditions. Fruit set differed signifcantly depending on the origin of pollen as well as on the presence of a pollen vector. None of these species produced fruits by the agamospermy tests, therefore indicating that they require the presence of pollen on the stigmas for fruit setting. By contrast, only G.... |
