Sepal

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A sepal (from Latin separatus "separate" + petalum "petal") is a part of the flower of angiosperms (flowering plants). Sepals in most flowers are green and lie under the more conspicuous petals. As a collective unit the sepals form a calyx, whereas the collection of petals is called the corolla. Together, these two structures are known as the perianth of the flower.

Sepals are usually green, regardless of petal color. However, the term tepal is usually applied when the petals and sepals share the same color, 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. The calyx (the sepals) and the corolla (the petals) are the outer sterile whorls of the flower, which together form what is known as the perianth.^[1]

The number of sepals in a flower (called merosity) is indicative of the plant's classification: eudicots have typically four or five sepals, whereas monocots and palaeodicots have three, or some multiple of three, sepals.

The form of the sepals vary considerably among the flowering plants. Often the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Examples of flowers with much reduced perianths are found among the grasses. In some flowers, the sepals are fused towards the base, forming a calyx tube (as in the Lythraceae family),^[2] a floral tube that can include the petals and the attachment point of the stamens.

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[edit] See also

• Plant morphology