When examining the anatomy of a flower, you will notice that there is often a ring of small leaves around the outside of the flower's petals. Each leaf is referred to as a sepal. Sepals are typically part of angiosperms, which are flowering plants. While they may seem insignificant, sepals serve a useful purpose in the growth and development of the flower.
Each sepal grows from the base of the flower, forming a ring around the stem. Collectively, the entire ring of sepals is called the calyx. The calyx lies below the collection of more prominent petals, known as the corolla.
Sepals are usually green, although they are sometimes brown. Still others may even be the same color as the petals, or are colorful themselves in the absence of petals. These are referred to as tepals.
The shape, size and number of sepals vary widely from one species to another. Some types of plants have four or five sepals. Others have either three sepals the more in multiples of three.
When the flower bud first starts to form, the sepals enclose the bud, protecting it. As the bud grows, the sepals will support the corolla. In some species, specialized sepals perform the same function as petals, directing pollinators to the flower.
In some species, sepals should not be confused with bracts. Bracts are specialized leaves that surround clusters of florets, such as in poinsettia plants.