When it comes to pollination, plants are quite ingenious and inventive. Some types shun showy petals and sepals preferring instead to pump their energies into producing large quantities of pollen grains which are then scattered into the wind, to be carried, hopefully, to the stigma of a similar species.
The Process of Wind Pollination
Wind pollination or anemophily is a process wherein pollen is carried by the wind from the male structures of a flower to the female structures of the same species. All the plants known informally as the gymnosperms and some angiosperms (flowering plants), particularly the monocotyledons, are anemophilous. Botanists estimate that only around 10%-12% of the total species of flowering plants are wind pollinated.
Angiosperms that are wind pollinated do not develop flowers with brightly colored petals nor do their flowers produce scents or nectar. This is in contrast to entomophilous (insect pollinated) and zoophilous (vertebrate pollinated) species who use color and scent to attract animal pollinators. Also, the pollen grains of wind pollinated species tends to be smaller and lighter than the pollen of animal pollinated types.
The pollen of wind pollinated plants tends to have less nutritional value to insects than the pollen of animal pollinated plants. This is not to say, however, that insects do not visit anemophilous plants. Insects will gather pollen from anemophilous flowers when pollen from entomophilous flowers is scarce.
Small solitary bees will often visit the small and inconspicuous flowers of the many species of grass while the larger bumblebees and honeybees can be seen gathering pollen from corn tassels.
Unfortunately for hay fever sufferers, almost all pollen types that trigger allergic reactions are anemophilous, especially that nasty ragweed pollen.
Wind Pollination is an Effective Transporter but not an Efficient Pollinator
To be successful wind pollinators depend on four conditions being met:
- The production and release of large amounts of pollen.
- Ample air circulation to carry the pollen away.
- Female plants being in close proximity.
- Dry weather to insure that rain does not wash the pollen out of the air.
Wind is a very effective transporter. It can take the tiny dry pollen grains as high as 19,000 feet and carry them for three thousand miles or so away from their parents. However, wind dispersal is totally haphazard and not a particularly efficient way of achieving pollination. Consequently, the overwhelming proportion of the billions of pollen grains produced by a single plant will fail to reach the stigma of another plant of their kind thus being wasted.
Because wind pollination is a primitive and wasteful condition, most wind pollinated flowers are found in temperate regions where individuals of the same species often grow close together. Conversely, there are very few wind pollinated plants in tropical zones where plants of the same species tend to be more widely distributed.
Wind pollinated flowers release huge amounts of pollen into the breeze and trust to luck that a few grains land on receptive female structures of the same species.
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