Tepal

A tepal is a segment of a flower’s perianth when the distinguishing features of sepals and petals are not clear. The perianth is the outer floral envelope and is traditionally divided into the calyx (sepals) and the corolla (petals). In many flowers, particularly among monocots, the sepals and petals are similar in shape, color, and size, so the components are described as tepals rather than as sepals or petals.

Tepals may be free or fused at the base. They can be arranged in various forms, from spreading to tubular, and they often appear petaloid, contributing to the flower’s visual appeal even though they do not represent a true calyx or corolla in a strict sense. Common examples include lilies (Lilium), tulips (Tulipa), and many members of the Amaryllidaceae and related groups, such as Allium species (onions and garlic) where the outer and inner perianth segments resemble petals.

Use of the term tepal helps plant description and classification when the perianth segments cannot be easily differentiated into sepals and petals. It is also employed in comparative botany to discuss morphological patterns across species where the border between calyx and corolla is blurred.

Etymology: the word tepal combines petal and sepal, reflecting its use for undifferentiated perianth parts. See also sepals, petals, and perianth.