Sexual Reproduction in Flowering Plants
Explain the a structure of a typical flower.
A structure of a typical flower consists of 4 floral whorls, viz., calyx, corolla,
androecium and gynoecium.
Calyx: The calyx is the outermost whorl of the flower and the members are called sepals. Generally, sepals are green, leaf-like and protect the flower in the bud stage.
Corolla: Corolla is composed of petals. Petals are usually brightly colored to attract insects for pollination.
Androecium: Androecium is composed of stamens. Each stamen which
represents the male reproductive organ consists of a stalk or a filament and an anther. Each anther is usually bilobed and each lobe has two chambers, the pollen-sacs. The pollen grains are produced in pollen-sacs.
Gynoecium: Gynoecium is the female reproductive part of the flower and is made up of one or more carpels. A carpel consists of three parts namely stigma, style, and ovary. The ovary is the enlarged basal part, on which lies the elongated tube, the style. The style connects the ovary to the stigma. The stigma is usually at the tip of the style and is the receptive surface for pollen grains. Each ovary bears one or more ovules attached to a flattened, cushion-like placenta.