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TEXTBOOK OF BOTANY 



to the same family, have also been found to be poisonous to 

 livestock if eaten in sufficient quantities. Another poisonous 

 member of the pulse family is the rattlebox. Still another 

 western poisonous plant that causes important losses, espe- 

 cially of sheep, is the death camas (Zygadenus). 



The leaves of the black cherry are poisonous when partially 

 wilted, and cattle are sometimes killed by eating the leaves 

 from cut branches. Some deaths have been reported, too, of 

 children who ate the kernels of black cherry seeds, or who 

 swallowed the fruits whole. The partially wilted leaves of 

 some other cherries and the kernels of many, perhaps of all, 

 cherries and plums, are poisonous. The sneezeweed, a com- 

 posite, which when powdered is used medicinally to produce 

 sneezing, has been known to kill sheep, cattle, and horses 

 which, unfamiliar with the plant, have eaten it. As a rule, 

 however, animals avoid the plant. Corn cockle, American 

 false hellebore, the buckeyes and the horse-chestnut, water 

 hemlock, poison hemlock, and the 

 broad-leaf laurel, already referred 

 to as poisonous to human beings, 

 are also dangerous to animals. 



356. Plants Poisonous to the 

 Touch. Well-known representa- 

 tives of this class are poison ivy, 

 poison oak, and the poison sumach 

 (poison elder). All these belong 

 to the same genus (Rhus) as the 

 common sumachs. Their irritat- 

 ing effects upon the skin are due 

 to an oil which is found in all 

 parts of the plant ; it is soluble 



in alcohol and is destroyed by an alcoholic solution of sugar 

 of lead. Some of the primroses produce a somewhat similar 

 irritation of the skin in many persons. The milky juices of 

 the caper spurge, snow-on-the-mountain, and other spurges 



FIG. 191. The poison ivy. 

 After Weed. 



