THE EVOLUTION OF VIVIPARY IN FLOWERING PLANTS

Vivipary in flowering plants is defined as the precocious and continuo us growth of the offspring when still attached to the maternal parent. Two main types, true vivipary (involving sexually produced offspring) and pseudovivipary (asexual offspring), may be identified. Vivipary h as been described from slightly less than a hundred different species of flowering plants, of which we classify approx. 50% as having true v ivipary, with the remaining species being pseudoviviparous. Species wi th true vivipary tend to inhabit shallow marine habitats while those w ith pseudovivipary are mostly found in arctic, alpine, or arid habitat s. We suggest that all of these by extraordinarily coarse-grained envi ronments for seedling establishment, albeit with major differences in patch size. In all of these situations the probability of an offspring being dispersed in time or space to a patch better than the parental parch is very low, hence taxa with seed dormancy or seed dispersal mec hanisms enjoy no particular advantage. We suggest that future research focus on species that are facultatively pseudoviviparous, as well as on comparisons of ecological and biomechanical aspects of viviparous a nd non-viviparous mangroves and seagrasses.