SECT. II 



PHANEROGAMIA 



631 



Cactaceae form a dominant constituent of the vegetation in the dry south- 

 western regions of the United States and in Mexico. They are also widely dis- 

 tributed in the West Indies and South America. A similar habit is found in some 

 Euphorbiaceae and Asclepiadaceae living under corresponding climatic conditions. 

 There are numerous epiphytic Cactaceae, especially species of Rhipsalis, Epiphyllum, 

 and Phyllocadus, which clothe the branches of trees and affect the general 

 aspect of the vegetation. 



Opuntia ficus indica has become naturalised in the Mediterranean region. The 

 fruits of this species and of 

 others of the genus are edible, 

 and the plants are cultivated 

 as fruit-trees. Some Cactaceae, 

 such as Anhalonium, contain 

 highly poisonous alkaloids and 

 saponine. The Cochineal insect 

 is grown upon species of Opuntia 

 and Nopalea (N. coccinellifera). 



Order 21. Thymelaeinae 



Shrubs or trees, with simple, 

 entire leaves, often closely 

 crowded. Flowers perigynous, 

 hermaphrodite, actinomorphic, 

 tetramerous or pentamerous. 

 Corolla often wanting. Stamens 

 in one or two whorls. Carpel, 

 one. Ovary with a single ovule. 

 Family 1. Thymelaeaceae. 

 Ovule pendulous. Daphne 

 Mezereum (Fig. 689) isa poisonous 

 shrub, possibly native to Britain, 

 which flowers in February and 

 March before the leaves appear. 

 The flowers are rose-coloured, 

 scented, tetramerous, and have 

 no corolla. The leaves form a 

 close tuft until the axis elongates. 

 The fruit is a bright red berry. 

 In the Alps and in the Medi- 

 terranean region there arc numerous species of Daphne, all of which are poisonous. 

 OFFICIAL. Daplnn' Mi^:reum, D. Laureola, and D. Gnidium yield MEZEKEI 



CORTEX. 



Family 2. Elaeagnaceae. Ovule erect. Hippophae. Elaeaynus. The leaves 

 and young twigs are covered with shining peltate hairs. 



Order 22. Myrtiflorae 



Leaves opposite, simple, entire, exstipulate; flowers hermaphrodite, 

 actinomorphic, tetramerous or pentamerous, hypogynous, or at most 



FIG. 68!i. Daphne Mezereum (J nat. size). OFFICIAL 

 and Poisuxiti'ti. 



