With its ability to reach a height of 20 to 30 feet, hibiscus can be an impressive plant for a tropical garden. However, it is the flower, not the plant's height, that appeals to most hibiscus admirers. The 4- to 8-inch-wide flowers come in a variety of colors. Because of their well-defined structures, hibiscus flowers are often studied in botany classes.
A Perfect Flower
Hibiscus flowers are perfect flowers (also known as complete flowers). This means each flower has both male and female reproductive structure, petals, sepals and a receptacle. An imperfect, or incomplete, flower is missing one or more of these features.
Petals, Sepals and Receptacle
The receptacle is the point on the stem to which the other structures attach. Sepals are small green petal-like structures that cover the petals before they emerge. Looking at a hibiscus flower from the back you will see five sepals radiating from the stem at the base of the flower. The hibiscus has five petals. The petals are unfused, meaning they are each separate from one another.
The pistil is the female reproductive part of a plant. The pistil is made up of the ovary where seeds develop, the stigma that catches pollen and the style that is the tube between the stigma and ovary. The ovary of the hibiscus is called superior because it sits within the petals rather than below them. Each hibiscus ovary has five chambers and so can produce five seeds. At the top of its style, the hibiscus has five branches that curve outward from one another. At the tip of each of these branches is a round stigma.
The male reproductive structure in a plant is called the stamen. It is made up of the anther that holds the pollen and a stalk called the filament on which the anther sits. In a hibiscus flower, the filaments fuse into a tube that surrounds the style. Numerous anthers stick out from the filaments almost like the feathers on a feather duster. The five stigma stick up above the anthers.