774 WEED FLORA OF IOWA 



indigenous to the United States," in which fifty plants were de- 

 scribed and illustrated. The high price of these books, however, 

 necessarily limited their distribution. 



In Rafinesque's "Medical Flora," published in 1828 and 1830, 

 one hundred and five plants are named as being native North 

 American plants. Among those listed are such weeds as mayweed, 

 butterfly weed, wormseed, wild hemlock, cowbane, thorn-apple, 

 fleabane, boneset, Joe-Pye weed and mullein. 



The most complete work of recent years is Millspaugh 's American 

 Medicinal Plants in which he describes and illustrates with colored 

 plates 180 medicinal plants native in the United States and recog- 

 nized by homeopathic physicians as of therapeutic value. He also 

 adds to each description, the active principles of the plant in ques- 

 tion, the method of preparation and the physiological action of the 

 drugs derived therefrom. In addition to the one hundred and 

 eighty plants fully described, he mentions hundreds of others that 

 are known to the profession but are not native to the United 

 States, making in all so satisfactory a treatise that for many years 

 it must remain our most reliable source of information in this line. 

 In Dr. Pammel's Manual of Poisonous Plants, many medicinal 

 weeds not of a poisonous nature are listed among the economic 

 plants. 



The United States Department of Agriculture has issued a num- 

 ber of bulletins containing references to medicinal weeds, which 

 are listed in the bibliography at the end of the volume. 



Many plants not listed as official in the United States Phar- 

 macopoeia have, nevertheless, value as commercial products. Such, 

 for instance, is true of the wormseed plant which, although not 

 recognized in our Pharmacopoeia, brings from 6 to 8 cents per 

 pound in the drug market. 



Quack grass (Agropyron repens) is the only weed of the grass 

 family that is official in the U. S. P. A fluid extract from the 

 rhizome of this plant sold under the name of dog grass or triticum 

 is a remedy in kidney and bladder troubles. 



The roots of various docks of the Iowa species are official. Bitter 

 dock (Bumex obtusifolius) and yellow dock (B. crispus) are rated 

 at 2 to 8 cents per pound and form the basis of various blood 

 purifiers. The leaves of sheep sorrel (B. acetosella) while not 

 official, are of market value. 



