Sepal
A sepal (from Latin separatus "separate" + petalum "petal")
is a part of the flower of flowering plants. Sepals in a "typical" flower are
green and lie under the more conspicuous petals. As a collective unit the sepals are called
the calyx, and the collection of petals is called the corolla.
Together, these two structures are known as the perianth of the flower. The
petals and sepals are usually differentiated into colorful petals and green sepals. The term
tepal is usually applied when the petals and sepals are not differentiated
and look similar or the petals are absent and the sepals are colorful. When the flower is in
bud, the sepals enclose and protect the more delicate floral parts within. Morphologically
they are modified leaves.