There are many other families of plants, some with irregular and others with regular flowers, that appear to group themselves around the Lamiaceæ, all of which agree, in spite of individual differences, in having a superior ovary. The remaining families of the gamopetalæ, however, always have an inferior ovary, usually obvious by the insertion of petals above the ovary, and in the fruit often conspicuous by the remains of the withered calyx still clinging to the top of the fruit. Only two of the scores of families, with inferior ovary and gamopetalous corollas, will be mentioned here, both of which are important. _Rubiaceæ_--Madder family. Common examples are the creeping bedstraw, the sweet woodruff, partridge berry, button bush, and bluets or quaker-ladies. All, except one of these, are herbs, but in the tropics the Rubiaceæ are nearly all shrubs or trees. Among those are the coffee, quinine, and ipecac. All the family have opposite leaves (a few verticillate) and stipules, regular flowers, with stamens as many as the corolla lobes, and alternate with them. The fruits are a drupe, berry, or capsule. Over 340 genera and 6,000 species are known almost throughout the earth. _Compositæ_ or _Carduaceæ_--The daisy family and the largest and most complex of all the plant families. As the culmination of the scheme of plant classification, they show the greatest perfection in the arrangements for cross-fertilization. For a description of their flower structure, see Chapter I, page 44, and Figures 43-45. Some of the Compositæ have no ray flowers, others are all ray flowers, but the great bulk of them bear both tubular and ray flowers in a single head. This may be single, or more commonly it is arranged in various kinds of clusters. Each head is surrounded at its base by one or more series of usually tightly overlapping bracts, incorrectly called a calyx by the unobservant. The Compositæ include over 900 genera and 11,000 species from all parts of the world. Most of them in America are herbs. Daisy, dandelion, dahlia, chrysanthemum, sunflower, boneset, chicory, lettuce, and scores of other examples could be cited, all herbs. In the tropics the Compositæ are more often trees and shrubs. The family contains many economic plants such as arnica, chamomile, artichokes, inula, and many others.