The fitness of self-progeny individuals is inferior to that their outcrossed counterparts, resulting in a reduction plant population’s ability survive and reproduce. To prevent self‐fertilization, angiosperms with hermaphrodite flowers may exploit variety mechanisms, including synchronous dichogamy self-incompatibility. Synchronous involves two flowering morphs, strict within-morph synchronizat...

†Background The trailing edges of species ranges are becoming a subject of increasing interest as the environment changes due to global warming. Trailing edge populations are likely to face extinction because of a decline in numbers and an inability to evolve new adaptations with sufficient speed. Discussions of character change in the trailing edge have focused on physiological, exomorphic and...

INTRODUCTION .................................................................. 346 Discussion of the problem ..................................................... 348 Pollen-tube frequency distributions ............................................. 349 Influence of growth of compatible pollen tubes upon incompatible pollen tubes.. .. 352 SUMMARY AND DISCUSSION ....................................

Some Malpighiaceae produce minute cleistogamous flowers in addition to showy chasmogamous flowers. Standard techniques fail to reveal how the cleistogamous flowers achieve self-fertilization. Fluorescence in longitudinal sections shows that the pollen germinates inside the indehiscent anther. The pollen tubes then grow down through the filament,. into the receptacle, up into the carpels, and in...