24 



THE SOURCE OF THE DRUG DIOSCOREA. 



pubescent beneath, and figures 6 and 7, illustrating rhizomes of 

 D. paniculata and its variety glahrifolia. 



"When Dioscorea glmica grows at Ioay altitudes its rhizome is less 

 branched and contorted than Avhen it grows in the mountains. In 

 the Aicinity of Washington. D. C, its rhizome is often as unbranched 

 as the rhizome of D. quatemata^ and might be mistaken for that 



Fig. 7. — Rhizomes of Dioscorea paniculata var. ijlubrifulia from Gloundale, Prince Georges 

 Co., MfL, collected by H. H. Bartlett. (Two-thirds natural size.) 



species, but its greater diameter still suffices to distinguish it from 

 D. paniculata. The form of rhizome which occurs most frequently 

 in the drug trade at the present time is well illustrated by figure 8. 

 This particular specimen was obtained through the kindness of 

 Mr. R. W. Proctor, of Cincinnati. Ohio. As a general rule, collectors 

 of Dioscorea who supply the drug market do not distinguish between 



189 



