B. P. I.— 591. 



THE SOURCE OF THE DRUG DIOSCOREA, WITH A 

 CONSIDERATION OF THE DIOSCORE,^: FOUND IN 

 THE UNITED STATES. 



TAXONOMIC HISTORY OF THE DIOSCOREiE OF THE UNITED STATES. 



Dioscorea, an extensively, developed genus in the Tropics of both 

 hemispheres, is represented in the eastern and central United States 

 by five species. Of this number, two are described for the first time 

 in this paper; the others have had a long and involved bibliographic 

 history. 



In 1705 Plukenet " published " Bryoniae nigrae similis floridana, 

 muscosis floribus quernis, foliis subtus lanugine villosis, medio nervo 

 in spinulam abeunte." In 1839 Gronovius '' referred Plukenet's 

 plant to Dioscorea, in the following account of a specimen which 

 Clayton had sent him from Virginia: 



Dioscorea foliis cordatis acuminatis, nervis lateralibus ad medium folii 

 terminatis. Mas. 



Bryoniae nigrae similis Floridana, etc. Plukn., Auialtb., p. 46, t. 375, f. 5. 



Lupnli species late scandens, foliis cordiformilms venosis, alia tlore, alia 

 semine foecnnda, flores albos steriles in spica pendnla ferens, seminibns mem- 

 branis extantibus alatis, vasculo qnoque seminali membranaceo triquetro 

 inclusis, pluriniis in racemos ad modnm Lupulorum dense congestis. Clayt. 

 n. 94. 



The only Dioscorea ascribed by Linnseus to the present area of 

 the United States Avas in part based upon the above citations from 

 Plukenet and Gronovius. He treated it as follows : " 



7. Dioscorea [villosal foliis cordatis alternis opposltisque, caule laevi. 



Dioscorea foliis cordatis acuminatis: nervis lateralibus ad medium folii 

 terminatis. Gron. Virg. 121. 



Bryoniae nigrae similis floridana, muscosis floribus quernis, foliis subtus 

 lanugine villosis: medio nervo in spinulam abeunte. Pluk. Aim. 46, t. 375, f. 5. 



Habitat in Virginia, Florida. 



In attempting to decide upon the application of the name Dioscoi'ea 

 villosa, it was but natural to inquire whether there was any speci- 

 men so called in the herbarium of Linnaeus. Dr. B. Daydon Jackson, 



« Amaltbeum, p. 46, t. 375, f. 5. 

 ^ Flora Virginica, e<l. 1, p. 121. 

 "Species IMautarum, ed. 1 (1753), ii, p. 1033. 



55838°— Bui. 189—10 2 7 



