Flowers have both male and female organs. The male organ is called the stamen and the female organ is called the pistil. Pollen is made at the top of the stamen, a small bulb called the anther. Before the flower can produce a fully developed seed, at least one grain of pollen must be transfered to the stigma, a sticky bulb on top of the pistil. From there, the pollen can tunnel down into the pistil and fertilize an ovule, creating a seed.
Wind pollination is the simplest method of pollination. Plants that use wind dispersal produce small, simple flowers and sometimes have no petals at all. Instead, they produce lots and lots of very light pollen on long stamens that stick out into the air. The wind catches the pollen, blowing it around at random. By chance, some of it is bound to land on the stigma of another plant, pollinating it.
Plants which are pollinated by animals often have bright, showy petals. These plants lure insects, bats or birds in to feed on their nectar. In the process, the animals rub against the pollen, which sticks to them. They then transfer the pollen to other flowers as they continue to feed. Plants use a variety of different schemes to draw animals to them. They may have fragrances that attract the animals, nourishing nectar, specialized shapes and eye-catching colors, or several of the above. Many flowers are specialized to attract a particular type of pollinator. Animals pollinated by flies and other carrion insects often have dull red, brown or purple coloring and a putrescent smell like rotting meat. Flowers adapted for butterflies will often have a large leaf which is easy for the butterflies to land on. Flowers which attract bees may have complex visual patterns which draw the bees into the center of the flower called nectar guides.