49 genera, with about 750 species; almost entirely confined to the Tropics; none in Europe or in N. Asia.—The seeds of the Cocoa-tree (T. cacao, bicolor, glaucum, etc., natives of Trop. Am., especially north of the Equator) are used for chocolate and are also officinal (“Cocoa-beans,” “Cocoa-butter,” “Oil of Theobroma”). Theobromine. Cola acuminata, Africa.
Fig. 440.—Theobroma cacao. Branch with flowers and fruits (⅙).
Figs. 441–442.—Theobroma cacao.
Fig. 441.—Diagram of the flower: st barren stamens.
Fig. 442.—B Seed in transverse section: n hilum. A Embryo after the removal of one of the cotyledons.
Order 2. Tiliaceæ. This differs from the other orders of the Columniferæ chiefly in the stamens being entirely free from each other, and also divided into many filaments, as far as the base, or at all events very far down, so that the flower appears to have numerous stamens or to be slightly polyadelphous (Fig. [443]); in addition to this, it may be observed that the anthers are 4-locular and introrse. In Luehea the groups of stamens alternate with the petals. In a few genera (Corchorus, Triumfetta) 10 free and single stamens are found in 2 whorls; but, in the majority, groups of free stamens in separate bundles. The stamens are more or less united in Apeiba, Luehea. Style simple. Ovary 2-locular. The ovules are pendulous; raphe turned inwards. The calyx readily falls off; the æstivation of the entirely free petals is slightly imbricate (not twisted).
