ANACARDIACEAE RHUS 



609 



Distribution. This plant is distributed from Nova Scotia to Wisconsin, 

 Utah, Arkansas and Florida. 



Rhus Verm.v L. Poisonous Sumac or Dogwood 



A shrub or small tree with pinnately compound leaves; leaflets 7-13, obo- 

 vate-oblong entire, smooth, or somewhat pubescent ; flowers polygamous in 

 loose slender axillary panicles ; drupe white, globose, oblong. 



Distribution. Found in the swamps from New England to Ontario to 

 Minnesota, Missouri, to Louisiana and Florida. 



Fig. 342. Poison ivy (Rhus Toxicodendron). a, spray showing aerial rootlets and leaves; 

 b, fruit both one-fourth natural size. (Chesnut, U. S. Dept. Agr.) 



Rhus diversiloba Torrey and Gray. California Poison Ivy 



Nearly glabrous, erect or climbing shrub ; leaflets 3 or rarely 5, obtuse or 

 deeply pinnately lobed ; flowers in loose axillary panicles ; drupes subglobose. 



Distribution. Common on the Pacific Coast from California to Washington. 



Poisonous properties. All three species are poisonous to many persons, 

 some persons being much more sensitive to irritation from the plants than 

 others Dr. J. C. White describes the effect of poison oak and poison ivy. He 

 had collected freely of the plant for many years without any disturbance. 

 Specimens were picked on September 28th, Oct. 6th, and Oct. 10th. He felt 



