Sepal

[4] The term sepalum was coined by Noël Martin Joseph de Necker in 1790, and derived from Ancient Greek σκέπη (sképē) 'covering'.

[5][6] Collectively, the sepals are called the calyx (plural: calyces),[7] the outermost whorl of parts that form a flower.

Sanskrit kalika 'bud'),[10] while calix is derived from Greek κύλιξ kylix 'cup, goblet'; both words have been used interchangeably in botanical Latin.

In some flowers, the sepals are fused towards the base, forming a calyx tube (as in the family Lythraceae,[15] and Fabaceae).

In other flowers (e.g., Rosaceae, Myrtaceae), a hypanthium includes the bases of sepals, petals, and the attachment points of the stamens.

The calyx (the sepals) and the corolla (the petals) are the outer sterile whorls of the flower, which together form the perianth.

In some species, the calyx not only persists after flowering but instead of withering, begins to grow until it forms a bladder-like enclosure around the fruit.

In a mature flower, the perianth consists of a calyx (sepals) and the corolla ( petals ) it supports.
Tetramerous flower of Ludwigia octovalvis showing petals and sepals
After blooming, the sepals of Hibiscus sabdariffa expand into an edible accessory fruit .
In many Fabaceae flowers, a calyx tube surrounds the petals.
The large calyx of the medlar fruit is the source of its vulgar nicknames.