SUMAC FAMILY. 137 



The plant is a perennial shrub, sometimes low and 

 erect and sometimes trailing or climbing by aerial root- 



Th Pi ^ s " ^ e l eaves are Pooled, and pinnately 



compound, with three irregularly ovate leaf- 

 lets, variously notched and toothed. Scarcely two leaves 

 on the same or different plants can be found alike, and this 

 proves a most valuable means for identification. The 

 inconspicuous flowers grow in loose panicles in the axils 

 of the leaves. The fruit is whitish and globular, with a 

 waxy appearance. 



Whenever practicable, Poison Ivy should be eradicated. 

 Where possible it is best to plow the land where it grows 

 and crop it until the ivy is killed. For places where this 

 cannot be done, Stone recommends a solution of one-half 

 to one pound of arsenate of soda dissolved in five gallons 

 of water. This should be applied in sufficient quantity 

 to soak into the soil and reach the roots. Five gallons is 

 sufficient to treat three to five square rods. 



WESTERN POISON IVY OR POISON OAK, Rhus Rydberyi 

 Small, a low shrub growing in the Rocky Mountain re- 

 gion, has the same effect as Rhus Toxicodendron. Unlike 

 the latter, it does not creep or climb, but always stands 

 erect, one to two feet high. The three leaflets are often 

 tinged with purple when young. The small, greenish 

 flowers are borne as in the eastern Poison Ivy, and the 

 shiny white fruit is similar. 



POISON OR SWAMP SUMAC, Rims Vernix L., is a shrub 

 or small tree sometimes attaining a height of twenty-five 

 feet. It is found in the eastern and central United States 

 and in Ontario, and produces effects similar to those of 

 Poison Ivy. The leaves are petioled and pinnately com- 



