Not all plants have flowers, but many that live on planet Earth today do. The flower, which is generally the showiest part of the plant is for sexual reproduction. Fragrance and color are devices to attract pollinators that play an important role in the reproductive process. (See my post on pollination)
Parts of the Flower --The flower can contain the male parts to produce pollen and/or the female ovule plus accessory parts such as petals, sepals, and nectar glands.
The pistil is the female part of the plant. It is generally shaped like a bowling pin and located in the center of the flower. It consists of the stigma, style, and ovary. The stigma is located at the top, and is connected to the wide base (ovary) by the style. The ovary contains the eggs which reside in the ovules. After the egg is fertilized the ovule develops into a seed.
The stamen is the male reproductive organ. It consists of a pollen sac (anther) and a long supporting filament. This filament holds the anther in position so the pollen it contains may be disbursed by wind or carried to the stigma by insects, birds or bats.
Petals are highly colored portions of the flower. Not all flowers have petals, like the spinach flowers above for example. The petals collectively are called the corolla. The number of petals on a flower is often used in the identification of plant families and species.
Types of Flowers-- If a flower has a stamen, pistils, and petals, it is called a complete flower. If one of these parts is missing, the flower is considered to be an incomplete flower. If a flower contains functional stamens and pistils, it is called a perfect flower. (Stamen and pistils are considered the essential parts of a flower.) If either of the essential parts is lacking, the flower is imperfect.
Pistillate (female) flowers are those which possess a functional pistil(s) but lack stamens. Staminate (male) flowers contain stamens but no pistils. There are plants which bear only male flowers (staminate plants) or bear only female flowers (pistillate plants). Species in which the sexes are separated into staminate and pistillate plants are called dioecious. There are a few plants like this, from my forestry classes I know holly, mulberry and pistachio trees are dioecious; Spinach, hops and asparagus are also dioecious; therefore, to obtain fruit from these plants, it is necessary to have female and male plants in the same area. Monoecious plants are those which have separate male and female flowers on the same plant. Corn plants and pecan trees are examples. Some plants bear only male flowers at the beginning of the growing season, but later develop flowers of both sexes; examples are cucumbers and squash.
I always enjoy getting E-mail questions about plants and growing, If you still have a question after doing a search on the blog feel free to E-mail me!
Good Growing,
Dr. E. R. Myers
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