168 



DE CANDOLLE'S SYSTEM. 



Broussonetia papyrifera. Hops, so valuable for their bitter- 

 ness, consist of the bracts and ripe fruit of Humulus Lupulus. 



Morus alba. 1. A male flower. 2. Clusters of females. 3. A female flower 

 separate. 4. The same with a part of the calyx cut away. 5. A vertical section of 

 a ripe achEenium. 6. A cluster of fruit consisting of baccate calyxes. 



149. Betulacea. Trees or shrubs. Leaves alternate, with 

 stipules. Flowers unisexual, amentaceous, monoecious ; males 

 sometimes having a calyx. Stamens definite, usually distinct. 

 Ovary superior, 2-celled ; ovules pendulous. Fruit mem- 

 branous, indehiscent, 1-celled. Seeds pendulous; albumen 

 none. 



USES. Timber trees, furnishing a light kind of wood. 



TYPICAL GENERA. Betula, Alnus. 



150. Myricacea. Leafy shrubs, with resinous glands and 

 dots, leaves alternate. Flowers unisexual, amentaceous, 

 achlamydeous. Stamens 6 or 8. Ovary 1-celled, surrounded 

 by several hypogynous scales ; ovule solitary, erect ; stigmas 

 2. Fruit drupaceous, or dry and dehiscent. Seed solitary, 

 erect ; radicle superior. 



USES. Aromatic shrubs. Sweet Gale, Myrica Gale, is 

 used in Sweden as a substitute for hops. The berries of the 

 M. cerifera, the Candleberry Myrtle, secrete a natural wax 

 from their surface ; its roots are astringent. Comptonia as- 

 plenifolia is used in North American medicine in diarrho?a. 



TYPICAL GENERA. Myrica, Comptonia. 



