The sepals form the calyx, also called calyx , and together with the petals of the corolla form the outer shell of a flower. Sepals are only used in the case of irregular flower envelopes, which are divided into calyx and crown; if all bracts are the same, these are called perigone .
Layout and function
The sepals are usually coarse and green. Typically they are like leaves or bracts , especially in their vascular bundle supply. The function of the calyx is to protect the flower when it is in bud . During the development of the buds, the sepals grow curved rapidly towards each other and touch each other. The sepals are often connected to one another by interlocking, cuticular gluing or hair. The edges are usually pushed one over the other. This increases the protection of the remaining flower organs developing inside the bud.
In chorisepal (= free calyx-leaved) flowers the sepals are free from each other, in gamosepal (= synsepal) flowers, however, they are fused.
The sepals originally serve to protect the flower bud, but in the derived case can strengthen the attractiveness of the petals. The calyx can also change its function and contribute to the spreading after the fruit has ripe. In the composites , the calyx is transformed into a wreath of hair, the pappus , which can be used to spread the wind or to attach to animals. The calyx can also take on the function of the crown as a display device, but this is usually associated with a reduction in the crown, for example in the Proteaceae . The calyx becomes crown-like (Corollinian). Another example is the common heather .
The term sepalum was generally used by Necker in 1790 for a perianth leaf . According to him, it is a made-up word that is derived from the ancient Greek word skepe "cover, cover". At least since A.-P. de Candolle In 1813, Sepalum is used in its current meaning.
The word calix was already used by Pliny in its current meaning. Leonhard Fuchs defined calyx in 1542 largely in its current meaning. Jungius 1678 and Ray 1682 call the calyx perianthium , in so far as it is logical, since the corolla was considered the actual flower at that time. Since Tournefort 1700, the current importance of Calyx has been established.
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