IV PREFACE. 



In the second part, or Medicinal Plants of Korth America, I have 

 presented a systematic arrangement and description of most of the 

 medicinal species, both indigenous and naturalized, which grow upon 

 this continent. I have not, however, endeavored to make the list 

 complete, but rather to exercise a judicious discrimination in selecting 

 the most important. Yery many species have been noticed merely to 

 condemn them ; still these often serve a useful purpose as examples of 

 orders or genera. 



Under the title, Character of the Order, are given the prominent 

 and characteristic features of the order as a whole ; and under the 

 title, Character of the Genus, the distinguishing characteristics of the 

 genus. In case only a single species of a genus is described, the char- 

 acter of the latter is omitted. 



Following the Description of a species are its Habitat, or place of 

 growth, the Part used medicinally, Constituents, Preparations, and 

 a brief account of its Medical Properties and Uses. 



The words, United States Pharmacopoeia, following the names of 

 parts used, or of preparations, signify that such parts or preparations 

 are official ; and official, throughout the work, signifies directed by the 

 Pharmacopoeia, the only recognized authority. 



Everywhere brevity and conciseness have been aimed at, but no- 

 where more than in the notes upon the medical properties and uses. 

 Here I have paid little attention to traditions, except when I could 

 trace them to a substantial foundation, believing that, in such matters, 

 a judicious scepticism is wiser than blind credulity. In general, I have 

 summarized the opinions of authors whom I consider most reliable, 

 and have also drawn freely from the records of my own experience 

 and observation. 



In the botanical part of the volume, I have followed no author ex- 

 clusively. Among those whose works I have most frequently con- 

 sulted are Baillon, Barton, Bentham, Bentley and Trimen, Bigelow, 

 Chapman, Figuier, Gray, Griffith, Lindley, Michaux, Porcher, Pursh, 

 Pafinesque, Torrey and Gray, and Woodville. I scarcely need add 

 that I have had constant access to specimens, both recent and dried ; the 

 latter either in my own herbarium or in that of Columbia College. 



The colored plates and a few of the illustrations on wood are from 



