FLOWER PARTS
Flowers provide plants with an enhanced mechanism for reproduction. The structure and arrangement of flower parts are adaptations for optimizing reproductive potential.

Flower parts are arranged in whorls or tiers borne on a central stalk. The tip of the stalk is the receptacle. The outermost whorl, or calyx, is composed of sepals. Sepals cover and protect the flower in the bud stage. The next whorl, or corolla, is composed of petals. Variation in corolla shape and color is associated with variation in the mode of pollination, be it by wind, bee, bird, or even bat.

Within the corolla are the parts directly associated with gamete production. Stamens are composed of a filament on which is supported the anther. Inside the anther are the pollen sacs where microsporocytes undergo meiosis to form microspores. Each microspore will develop into a pollen grain, the immature male gametophyte. The final whorl of flower parts comprises the pistil. A pistil is made up of one or more carpels. Each carpel has a stigma that connects via a style to the ovary. Inside the ovary are ovules that contain megasporocytes, within which the egg will form and fertilization will occur.