Flowers won't produce seed without pollination. The pollination of a flower requires interaction with a host of outside forces that affect plant propagation. The transfer occurs between cones in pine trees and other gymnosperms. Plants can self-pollinate or cross-pollinate.
Pollination is the transfer of pollen grains from the anther of one flower to the stigma of another, usually on a different plant. Pollination enables the reproduction of future generations of plants. The transfer results in the production of seeds.
Plants usually need to cross-pollinate. However, some species of plants have the ability to self-pollinate. Self-pollination is called autogamy. A plant that self-pollinates transmits an exact replica of the parent's genetic makeup to the offspring. Some plants self-pollinate by necessity due to location. Plants that can self-pollinate include peanuts, tomatoes and strawberries.
Cross-pollination (syngamy) refers to the transfer of pollen between different plants of the same species. This type of pollination occurs most frequently in nature, with the U.S. Forest Service estimating that up to 80 percent of all flowering plants are cross-pollinated. Cross-pollination occurs when an insect or animal moves tiny bits of pollen from the female to the male portions of two different flowers. This happens by the most ordinary circumstances of an insect brushing against a flower. Pollen adheres to the legs or wings and gets transported to another flower. Cross-pollination creates strong future generations with increased genetic diversity.
Water pollination can occur among water plants. This process, called hydrophily, involves the transfer of pollen by a water source. Pollen floats on the surface of a stream or pond for transmission to a distant flower. Water and pond weeds pollinate in this manner.
A strong gust of wind can transport pollen grains to another plant of the same species. This type of pollination typically occurs in plants that don't produce flowers, such as ragweed and conifers. Wind-pollinated flowers tend to have very little scent and don't produce nectar. However, these plants have elongated stigmas that often extend above a plant to catch the pollen grains blowing in the breeze.