ANACARDIACEAE 



CASHEW FAMILY 



POISON IVY. POISON OAK 



Rhus Toxicodendron L. 



Poison Ivy or Poison Oak contains a nonvolatile oil 

 which if it comes in contact with the skin may produce 

 the irritation and blistering that is commonly called 

 Ivy poisoning. 

 Some persons are 

 immune to it and 

 others are very 

 susceptible; cases 

 are Imown both of 

 persons who were 

 very susceptible in 

 youth but became 

 immime or nearly 

 so later, and of 

 others immime for 

 years, who late r 

 were victims of the 

 poisoning. Susceptible persons 

 who come in contact with Poison 

 Ivy should wash the hands and 

 face as soon as possible. Water 

 alone will help but strong soap suds 

 or solutions of sugar of lead or 

 chloride of iron are better. 



The plant is common from Nova 

 Scotia to British Columbia and 

 south to Florida and Mexico, blooming in June and July. 

 It will grow almost anywhere except in low peaty soil. It usu- 

 ally grows as a densely fine-hairy vine, climbing by means of 

 aerial roots, and will climb trees more than loo feet tall. Oc- 

 casionally it is found growing as an erect shrub. 



The flowers are similar to those of the Smooth Sumach, 

 page 184, but they are arranged in a loose panicle, and the 

 fruits are white. One must learn to recognize the plant, however, 

 by its petioled, trifoliate and more or less downy leaves. The 

 leaflets are ovate or round-diamond shape, 1-4 inches long, 

 mostly acuminate, entire, finely round toothed or coarsely few 

 toothed or lobed, and short soft hairy beneath. 



Poison Sumach or Poison Dogwood, Rhus Vernix L., is our most 

 poisonous species. It is common in the swamps of Lake county 

 and probably nowhere else in the state. It grows as an upright 

 shrub 6-15 feet high and has smooth, pinnate leaves with 7-13 

 ovate-oblong, entire leaflets. 



185 



