An inflorescence consisting of a head of small closely packed stalkless flowers or florets arising at the same level on a flattened axis. The whole is surrounded or subtended by an * involucre of bracts and simulates, in appearance and function, a single large flower. The capitulum is typical of members of the family Compositae. Capitula are often made up of two distinct types of floret: disc florets, in which the corolla tube terminates in five short teeth; and ray florets, in which the tube is extended into a conspicuous strap. When both types of floret are present the disc florets form the centre of the capitulum and the ray florets are arranged around the edge, giving a daisylike flower. Some composites have ray florets only, e.g. dandelions (Taraxacum) and chicory (Cichorium intybus), while others have only disc florets, e.g. thistles (Carduus, Cirsium) and cornflower (Centaurea cyanus). |
