174 ARTHUR-BISBY— TRANSLATION OF SCHWEINITZ'S 



with nearly 4,000 species and 250 genera, was presented to the scien- 

 tific world through the Transactions of the American Philosophical 

 Society, having been transmitted to the Society April 15, 1831, and 

 issued in printed form about a year later. It is usually spoken of as 

 a " Synopsis of North American Fungi " from the secondary title 

 used at the top of the pages. 



It seems, therefore, especially fitting that on the centennial anni- 

 versary of Schweinitz's election to membership, the Society should 

 take cognizance of his eminent and invaluable services to science, 

 encouraged and aided as they were by the Society's approval. 



No second attempt has followed Schweinitz's effort to present 

 a full survey of the fungous flora of North America until recently, 

 when the " North American Flora," to include all classes of plants 

 from the highest to the lowest, was projected and supported by the 

 New York Botanical Garden. In this work the fungi are to occupy 

 ten or more imperial octavo volumes, and the text is to be supplied 

 by many specialists. One volume is to contain the Uredinales, or 

 rusts, and its preparation has been intrusted to the senior writer of 

 this article, aided by the junior writer and other mycologists. In 

 pursuance of this work it has become necessary to know definitely 

 the extent of the contribution to the subject made by Schweinitz, an 

 amount so considerable in fact that his name is encountered by the 

 systematic student of the American rusts in much the same way that 

 the name of Linnseus is encountered by the student of the flowering 

 plants. The result of the detailed examination of the specimens in 

 the Schweinitz herbarium, now deposited with the Academy of 

 Natural Sciences of Philadelphia, and the interpretation of his pub- 

 lished account in the light of this study of his original material, are 

 presented to the Society in the following annotated translation from 

 the Latin into English of that portion of Schweinitz's works pertain- 

 ing to the rusts. 



In Schweinitz's day the rusts were not recognized as a distinctive 

 and sharply defined group of fungi, as they now are, but were to 

 some extent classed with other fungi occurring on living or languish- 

 ing hosts. They are all of microscopic size, but usually produce 

 some characteristic discoloration or hypertrophy of the substratum, 

 which aids in making them noticeable. In a few instances these 



