CLASSIFICATION OF ANGIOSPERMS. 



513 



The inner bark of the red or slippery elm (Ulmus fulva) is 

 used in medicine on account of its mucilaginous character (see 

 Fig. 119, C). The tree has a gray, fragrant bark; leaves which 

 are very rough above and become fragrant on drying, and the 

 wood is reddish-brown. The samara is not hairy as in some of 

 the other species. 



FIG. 284. View taken in Ceylon of a part of a grove of 4-year-old rubber trees (Ficus 

 elastica). This tree is extensively cultivated in Ceylon and other portions of tropical Asia, 

 and most all of the Asiatic rubber is produced by this tree. The trees may be tapped when 

 25 years old, and for 50 succeeding years yield 40 pounds caoutchouc every 3 years. 

 Reproduced by permission of The Philadelphia Commercial Museum. 



b. HORACES OR MULBERRY FAMILY. The mem- 

 bers of this family are herbs, shrubs, or trees, many of them con- 

 taining a milk-juice or latex. There are many representatives in 

 the tropical regions and some in temperate regions. The flowers 

 are unisexual, with a 4- to 5-parted perianth, and occur in spikes 

 or ament-like clusters. 



Cannabis sativa. This is the plant yielding hemp and also the 

 33 



