Many plants are pollinated by bees, birds or other animals, but not all flowering plants rely on other organisms to carry pollen from one flower to another. Approximately 20 percent of flowering plants are wind-pollinated.
Features and Appearance
Wind-pollinated plants don't depend on the ability to attract birds or insects, so their flowers tend to be small, drab, unscented and inconspicuous. Anthers (structures where pollen is produced) and stigmata (structures where the pollen will land) often project from the flower in order to be exposed to the wind.
The Sneeze Factor
Pollen produced by a wind-pollinated plant is -- quite literally -- blown on the wind, so much of it will land in places where it will do no good. Consequently, wind-pollinated plants need to produce large amounts of pollen. For people with pollen allergies, the considerable quantities of pollen produced by some wind-pollinated plants can be a vexing problem.
Other Wind-Dependent Species
Trees and grasses in temperate regions are often wind-pollinated. Trees in this category typically flower in early spring before their leaves arrive to ensure the leaves do not block the breeze and prevent pollination.