calycle

A calycle is a structure found in some botanical contexts, referring to the collective term for the sepals of a flower. These are the outermost whorl of floral leaves, typically green and leaf-like, that enclose and protect the developing bud. In some cases, the calycle can be fused into a tube or cup shape, while in others, the individual sepals are distinct. The term is not as commonly used as "calyx," which refers to the entire whorl of sepals. However, "calycle" can be employed to describe a secondary outer whorl of bract-like structures that may surround the true calyx, particularly in certain families like the Asteraceae. These outer structures can vary in size, shape, and texture, and their presence or absence can be a distinguishing characteristic for taxonomic purposes. The function of the calycle, like the calyx, is primarily protective. It shields the delicate inner floral parts from mechanical injury, desiccation, and sometimes herbivory before the flower opens. The appearance and composition of the calycle can also play a role in attracting pollinators, though this is less common than the role of petals.