42 BOTANY. 



small extent soluble in water, and the solution has an acid reaction. It 

 yields a light yellow precipitate with acetate of lead. The part of the alco- 

 holic extract that is insoluble in water is easily soluble in alkalies. It also 

 dissolves in nitric acid at a moderate heat, whereby oxydation takes place. 

 On addition of water, a yellow, brittle mass is precipitated." The Mexi- 

 cans are said to use an infusion of the leaves for bathing in, in rheumatic 

 affections. See Vol. Ill, Wheeler's Reports, pp. 608-9. 



Rhus diversiloba, T. & G. Poison Oak, Yeara. — Much like our poison 

 oak of the Eastern States. Common on the Pacific coast. For remedy see 

 Grindelia robusta. 



Negundo aceroides, Moench. Box-Elder. — Bearing in mind the great 

 success of the experiments with this tree in Kansas and Nebraska, .and its 

 wide range over the more arid areas of our Southwest, it may be well to 

 remember it in further attempts at tree culture. Though hardly to be 

 considered as a valuable timber, it may fairly be reckoned on the shade 

 and fuel list, and fairly associated in this respect with the following: 



Schinus molle, Linn., from Mexico and South America. — Now 

 grown in Southern California under the name of Pepper Tree and Chili 

 Pepper. 



Prosopis juliflora, DC. Mesquit. Algaroba of the Mexicans. — Grows 

 from Southeastern California east to Texas, where it attains the tree size, and 

 forms dense thickets; extends south into South America. The gum exud- 

 ing from this tree closely resembles gum arabic in appearance and in its 

 properties, and may some day become an important article in trade. The 

 pods while. yet in pulpy condition are a valuable forage, eagerly eaten by 

 animals, and on which they actually thrive while making hard marches. 

 The beans contain thirty per cent, of grape-sugar. Dr. Loew asserts that 

 the Comanche Indians prepare an alcoholic beverage from them. As a 

 fuel it ranks with the hickory of the Eastern States, and the charcoal made 

 from it is said by Dr. Loew to be of the best quality for metallurgical and 

 smelting purposes. Besides this species, there is another, hardly less useful, 

 i. e., P. pubescens, Benth., the Screw-Bean, the pods of which are ground 

 into flour by the Indians. The wood of both species is of great value in 

 some of the arts. 



