Vol. XV, pp. 147-149 June 20, 1902 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



TWO NEW SPECIES OF POISONOUS SUMACHS 



FROM THE STATES OF RHODE ISLAND 



AND FLORIDA. 



BY EDGAR A. MEARNS. 



Mr. Gerrit S. Miller, Jr., recently directed my attention to 

 marked variations in the lihics, known as Poison Oak and Poison 

 Ivy growing in the vicinity of his residence in Virginia. As I 

 justifiably considered myself to be practically immune to the 

 poison of these plants, comparisons were commenced, in the course 

 of which it developed that the Hhus radicans of Linnteus 

 (Poison Ivy), an extremely variable species of the North, meets 

 the range of Rhus toxicodendron of Linnceus (Poison Oak), a 

 southern sj^ecies, in Virginia and the District of Columbia. 

 Mhus toxicodendron Linnreus appears to be confined to the 

 Southern States. It is a shrub having crenately-lobed, very 

 pubescent leaflets. 



Seeds of Rhus radicans which I collected in Virginia, in No- 

 vember, 1901, were found to differ from those gathered on the 

 island of Rhode Island, near Newport, during the same month, 

 as well as from those labelled Rhus toxicodendron Linnaeus by 

 Mr. E. S. Steele, whose specimens (Nos. 364,079 and 364,080, 

 U. S. National Herbarium) were collected in the District of 

 Columbia, and kindly lent me, together with other specimens 

 of Rhus, by the authorities of the United States National 



26— BIOL. SOC. V7ASH. Vol. XV, 1902. (147) 



