SYNCARPY AND ALTERNATIVE MODES OF ESCAPING DISADVANTAGES OF APOCARPY IN PRIMITIVE ANGIOSPERMS

Summary In most groups of the angiosperms the primitive condition of apocarpy has been surpassed by syncarpy, which is a more advantageous construction in several respects. It enables (1) more regular pollen tube distribution, (2) intensified pollen tube selection, (3) higher economy of construction, (4) increased diversity of dispersal types in the fruiting stage. In primitive angiosperms there are alternative evolutionary trends exhibiting modified apocarpy or unelaborated syncarpy with some unusual differentiations (extragynoecial compitum, hyperstigma). These alternative methods share some, but not all advantages of usual elaborated syncarpy. It is supposed that, therefore, they were, like normal apocarpy, not competitive enough compared with perfect syncarpy.