ABSTRACT
The genus Centaurea includes about 400 to 500 species. Most of these are native to the east Mediterranean, with a few representatives in Europe. The cornflower, Centaurea cyanus L., is a hardy annual used in gardens and for cut flowers. The main color is “cornflower blue” with a wide spectrum of color variations including white, pink, purple-red, and picotee. In the winter the plants form rosettes, with the leaves pressed to the ground. There are two species in North America and one in Australia; most are herbs or small shrubs, and include annuals, biannuals, and perennials. Several species are used as ornamentals for bedding, foliage, or as cut flowers. Flowering is always preceded by some stem elongation, although under special experimental conditions it is possible to induce stem elongation without flowering. The rate of elongation and flowering is faster in older than in very young plants.
