Fig. 38.—Part of the head of flowers of Rondeletia. in p. 87, and may see the general resemblance which connects the two plants in the same order, and the differences which mark them to be of different genera. Fig. 38 is a tuft of flowers of Rondeletia odorata. Wendlandia is nearly allied to Rondeletia; as is the magnificent Portlandia grandiflora, which somewhat resembles Brugmansia lutea in shape though not in colour, as its flowers are white.
THE GENUS COFFEA AND ITS ALLIES.
The Coffee-tree (Coffea arabica) differs from the other Rubiaceæ in the tube of its calyx being very short and disappearing when the ovary begins to swell; and in the filaments of the stamens being sufficiently long to allow the anthers to be seen above the throat of the corolla (see a in fig. 39). The limb of the corolla (b) is five-cleft, and the style (c) bifid. Each ovary when its flower falls, becomes distended into a berry (d) or rather drupe, containing the nut e, in which are two seeds, flat on one side, and convex on the other, which are placed with the flat sides together, as shown at f; each seed having a deep longitudinal groove, as shown at g. These seeds are our coffee.
Fig. 39.—Coffee. (Coffea Arabica.)
The flowers of Ixora coccinea have the same general construction as those of the other plants of the order. The calyx has an ovate tube, and a very small four-toothed limb; and the corolla is salver-shaped, with a long and very slender tube, and a four-parted spreading limb. There are four anthers inserted in the throat of the tube of the corolla, and just appearing beyond it, and rising a little above them is the point of the style with its two-cleft stigma. The berry is two-celled, but it differs from that of the coffee in retaining the lobes of the calyx, which form a sort of crown. There are many kinds of Ixora, all stove shrubs, and all conspicuous for their large heads or rather corymbs of showy flowers. The genus Pavetta has been divided from Ixora, principally because the species composing it have the style projecting considerably beyond the corolla, instead of only just appearing above it.
The drug called Ipecacuanha is the produce of two plants belonging to this order, Cephælis Ipecacuanha and Richardsonia scabra; though a spurious kind is made from the roots of three species of Viola, all natives of South America, and a still inferior one from the roots of a kind of Euphorbia, a native of Virginia and Carolina. It is important to know this, as the best kinds possess tonic properties as well as emetic ones, while the inferior kinds are only emetics, and they are very injurious if taken frequently. The best brown Ipecacuanha is the powdered root of Cephælis Ipecacuanha; a plant with small white flowers collected into a globose head, which is shrouded in an involucre closely resembling a common calyx. The true calyx to each separate flower is small and roundish, with a very short five-toothed limb. The corolla is funnel-shaped, with five small bluntish lobes. The anthers are inclosed in the corolla, and the stigma, which is two-cleft, projects only a little beyond them. The berries are two-celled and two-seeded, and they retain the lobes of the calyx. The root is fleshy and creeping. Richardsonia scabra, which produces the white Ipecacuanha, has its flowers also in heads, but the calyx is larger in proportion to the corolla, and the stamens and style are both visible. The capsule contains three or four one-seeded nuts, crowned by the calyx; which, however, becomes loosened at the base, and falls off, before the seeds are quite ripe. Cephalanthus, Spermacoce, and Crusea, are nearly allied to Richardsonia.
The above plants all agree, more or less, with Cinchona, in their qualities, and they are all included by Dr. Lindley in the order Cinchonaceæ.
THE GENUS GALIUM AND ITS ALLIES.