involucri

Involucri is a term used in botany to describe a whorl or set of bracts subtending a flower or inflorescence. These bracts are typically leaf-like in appearance but are often smaller and may differ in color or texture from the foliage leaves. The primary function of an involucrum is to protect the developing flower or inflorescence before it opens. In some species, the involucral bracts can be quite conspicuous and play a role in attracting pollinators, sometimes even resembling petals. The arrangement and number of bracts in an involucrum can vary greatly among different plant families and genera. For example, in the Asteraceae (sunflower family), the involucrum is a prominent feature, forming a cup-like structure around the capitulum, which is a type of composite flower head. The individual bracts in such an involucrum are often called phyllaries. In contrast, some plants may have a reduced or absent involucrum. The presence, absence, and characteristics of the involucrum can be important diagnostic features for plant identification. It is a key characteristic in understanding the morphology of flowering plants and their reproductive structures.