194 SYSTEMATIC BOTANY. 



manufactories, and in making charcoal. Its bark is made 

 into slioes, boxes, etc. It is used in tanning leather, and 

 from it an oil is distilled which gives the peculiar scent 

 to Russian leather. The Indians use the bark of the 

 Paper Birch {B. papyracea) for making the " birch-bark 

 canoes." The wood of the Alder {Alnus) is very durable 

 only under the ground or water, used also for charcoal. 

 Sometimes it is manufactured into wooden bowls and 

 other utensils, and the bark is used in dyeing and tanning. 

 II. Urticaceae. A large family (more than two thou- 

 sand species), including the Elms, Mulberries, Nettles, 

 Hemp, Hop, etc. They are mostly diclinous plants, with 

 superior one-celled ovary. The American, or White Elm 

 ( TJlmus Americana), is one of the most magnificent of all 

 trees, and is everywhere found as an ornament in large 

 grounds. The timber is durable only when kept continu- 

 ously dry, or else entirely under water or in the ground. 

 The timber from the Slippery Elm (JJlmus fidva) is more 

 valuable, its mucilaginous inner bark is used in medicine 

 and surgery. The Hemp {Cannabis saliva) is a native 

 of India, where the inhabitants make from the dried 

 leaves, stems, and flowers an intoxicating drink called 

 Hashish. The plant is cultivated in all temperate and 

 warm countries for its fibre, which is used for cordage. 

 The Hop {Humulus Lupulus) is indigenous to North 

 America, temperate Europe, and Asia. It is cultivated 

 for Lupulin, a bitter substance developed in fertile flower- 

 clusters, and used in the manufacture of beer, ale, etc. 

 The Bread-Fruit-tree (Artooarpus incisa) of the Pacific 

 Islands, twenty to thirty feet high, has a fleshy receptacle, 

 and agglomerated carpels in the form of a mass as large as 

 a man's head. This is gathered before ripe, baked, and 



