Seed dispersal provides a template upon which the demographic processes of plant life cycles operate and, most importantly, seed dispersal determines the spatial distribution of genetic variation. Here, we review recent studies on seed dispersal by water (hydrochory) in species of Hibiscus to elucidate the potential ecological and evolutionary consequences of hydrochory at different spatiotemporal scales. We consider seed dispersal related processes that determine the distribution and dynamics of genetic variation, that is, the spatial shuffling effect of the seed bank that modifies genetic make-up within a population, the formation of a genetic reservoir within a metapopulation, and lineage dispersions and speciation that may produce patterns in plant phylogeography. Seed movement patterns within ecological time and space are likely to leave non-random patterns in long-term plant evolution and phylogeny.