Why Are Some Trees Pollinated by Wind And Some by Insects?
Pollen is to trees what sperm is to animals. It carries the tree’s male genes; it is the male fertilizing unit of woody plant reproduction. Typically, pollen appears in spring as a powdery cloud of fine, yellowish grains. Each tiny grain is a single cell, encased in a tough, ridged, or spiked coating. When inhaled by susceptible people, these grains can cause nasty allergic reactions. But they are absolutely essential for the continuing life cycle and evolution of trees. Pollination is the movement of these pollen grains from the male reproductive part of a plant to the female reproductive part. It is a prerequisite to fertilization, which occurs when the sperm-making pollen is united with the egg-containing ovary of a plant of the same species. If all goes well, the making of pollen, the subsequent act of pollination, and the biological marvel of fertilization all lead to the growth of fruits and seeds. This is a very good deal. Not only is it the basis for agricultural food productio
