ANGIOSPERMAE 



651 



as in many tropical trees, hang limply downwards. The flowers are borne on 

 the main stem or the older branches, and arise from dormant axillary buds 

 (CAULIFLOUY). Each petal is bulged out at the base, narrows considerably above 

 this, and ends in an expanded tip. The form of the reddish flowers is thus some- 

 what urn-shaped with five radiating points. The pentalocular ovary has numerous 

 ovules in each loculus. As the fruit develops, the soft tissue of the septa extends 

 between the single seeds ; the ripe fruit is thus unilocular and many-seeded. The 

 seed-coat is tilled by the embryo, which has two large, folded, brittle cotyledons. 

 Cola acuminata and C. vcra, natives of tropical Africa, yield the Kola nuts which 

 are used in medicine. 



OFFICIAL. Theobroma Cacao, from which OLEUM THEOBEOMATIS is obtained. 



Orders 15-17 are connected by a number of characters such as 

 reduction in number of stamens, presence of a disc, one-seeded loculi 

 in the fruit ; these may indicate a common relationship to the 

 Tricoccae or to the forms from which the latter order came. 



Order 15. Gruinales 



The flowers of the majority of the plants belonging to this order 

 are hermaphrodite, pentamerous, and radially symmetrical, with a 

 superior, septate ovary. K 5, C 5, 

 A 5 + 5, G (5). When the flowers 

 are zygomorphic they frequently ex- 

 hibit reduction (Polygalaceae). Stamens 

 coherent at the base, obdiplostemonous 



FIG. 672. Floral diagrams of Geraniaceae. A, Geranium 

 pratense. B, Pelargonium zonale. (After EICHLER.) 



FIG. 673. Fiuit of Pelargonium in- 

 quinans. (x 3. After BAILLON.) 



or haplostemonous. Nectaries to the outer side of the stamens or 

 as an annular disc within the stamens (Rutaceae). Ovules usually 

 pendulous, with the micropyle directed upwards and the raphe ventral ; 

 or the micropyle is downwardly directed and the raphe dorsal. 



Family 1. Geraniaceae. The genera Geranium with actinomorphic and Pelar- 

 gonium with dorsiventral flowers both have stalked, palmately- veined leaves. 

 Two ovules in each loculus. When ripe the five beaked carpels separate from a 

 central column, and either open to liberate the seeds, or remain closed and by the 

 hygroscopic movements of the awn-like portion bury the seed in the soil (Fig. 

 673 ; cf. Fig. 275, p. 334). 



