Compositae

Compositae, the largest natural order of flowering plants, comprising some 10,000 species in about 1,000 genera, or one-tenth of all known flowering plants, equally divided between the Old and the New World. They are herbs, or sometimes shrubs, with exstipulate leaves, and small flowers crowded into a capitulum or head (once called a compound flower), surrounded by an involucre of bracts. These florets may be of two kinds, the outer or ray having ligulate corollas, whilst the central ones or disk are tubular. They may also differ in sex. There are five sepals, though seldom with a recognisable limb, five united petals, five stamens, which are very characteristic in being epipetalous and syngenesious, and two carpels united into a one-chambered, one-ovuled inferior ovary with a bifurcate style. The order falls into three suborders: - Liguliflorae or Cichoriaceae, with florets all ligulate, and a milky latex, including the chicory, endive, lettuce, salsafy, dandelion, etc.; the Tubuliflorae, with all the florets tubular, as in the thistles, or with the outer only ligulate, as in asters, daisies, sunflowers, etc.; and the Labiatiflorae, with bilabiate florets, a small group mainly South American. Besides many other showy plants, such as Dahlia, Chrysanthemum, Cineraria, etc., the order contains many aromatic, bitter, and tonic plants, such as the wormwoods (Artemisia), and some that are acrid and poisonous, such as Arnica.