THE ORDER RUBIACEÆ: ILLUSTRATED BY THE CINCHONA, OR PERUVIAN BARK; LUCULIA GRATISSIMA; CAPE JASMINE; RONDELETIA; COFFEE; IXORA; IPECACUANHA; MADDER; GALIUM; WOODRUFF; AND CRUCINELLA STYLOSA. This order contains more than two hundred genera; but by far the greater part of these are composed of tropical plants, many of which are not yet introduced into Britain. Several of the genera, on the other hand, are British weeds; and this difference in habit, with others in the qualities of the plants, &c., have occasioned some botanists to divide the order into two: one of the new orders being called Cinchonaceæ, and containing the plants most resembling Cinchona; and the other Galiaceæ, containing the plants most nearly allied to Galium or Bedstraw. The characteristics of Rubiaceæ, in its most extended sense, are that the ovary is surrounded by the calyx, and placed below the rest of the flower; and that the corolla has a long tube, lined with the dilated receptacle, in which the stamens are inserted. In most of the species, the filaments are very short, and the anthers nearly or entirely hidden in the corolla; and in many cases, the segments of the calyx remain on the ripe fruit, as they do in the genus Pyrus in Rosaceæ, where they form what is called the eye in the apple and pear. The qualities of the Cinchona division of the Rubiaceæ are generally tonic; but some of the plants, as for example the Ipecacuanha, are used as emetics, and one (_Randia dumetorum_) is poisonous. The qualities of the Galium division are not so decidedly marked; but the roots of some of the plants are used for dyeing. THE GENUS CINCHONA, AND ITS ALLIES. [Illustration: FIG. 36.—CINCHONA, PERUVIAN BARK (CINCHONA LANCEOLATA).]