XVI International Botanical Congess
A number of angiosperm lineages have adapted to life in lakes, rivers, and oceans. Notwithstanding the extraordinary physiological adaptations required for this transition, there were also pressures on pollination mechanisms. One solution for aquatic angiosperms was to elevate their flowers above the water surface where pollination could proceed using mechanisms common to their ancestors. There were also advantages to pollination mechanisms that occur on or below the surface and within the water. Hydrophilous pollination in aquatic angiosperms is abiotic involving the interaction of biology and fluid dynamics. The most exemplary mechanism involves the seagrasses, which are analogous to wind-pollinated plants in that reproductive structures modify flow. Unlike other plants, however, seagrasses have mm-long pollen that rotate in the modified flow around flowers, which increases the potential for pollination.