488 PROCEEDINGS OF THE AMERICAN ACADEMY. 



As a lecturer he was peculiarly happy, for to the authority of a 

 master he added a clear style, the faculty of bringing essential points 

 into strong relief, and a humorous quality, which riveted the attention 

 of his hearers; but even more important than his lectures was his 

 work with students in research. Here his inspiring personal teaching 

 — for he never left them to an assistant — developed many distin- 

 guished students, among them such masters as Roland Thaxter, 

 William Trelease, W. A. Setchell, Kingo Miyabe, and Herbert M. 

 Richards. 



His scientific papers average three a year for the whole forty-five 

 years of his active work, if the papers of his students are included, as 

 they should be. They have been characterized as " clear, concise and 

 accurate," the well-considered careful utterances of a master, who 

 never yielded to the temptation of rushing into print, and also was 

 chary of establishing new species out of the great wealth of material 

 at his disposal, since he had a profound contempt for bad species, as 

 shown by his caustic remark about the manufacturers of them. 



"If a difference can be imagined, it is a new species; if it can be 

 seen, it is a new genus." 



Nearly two-thirds of his papers have to do with fungi, including the 

 studies of plant diseases already mentioned; while somewhat less than 

 one-third deal with algae, many of these with the contamination of 

 water supplies by them. One published in 1879 was reprinted 38 

 years later by Professor Whipple as "one of the classics of state 

 sanitation." It is written in a popular style, as are several of his 

 papers on fungi. 



Other useful papers consist of reports on the cryptogams collected 

 by various exploring expeditions and of lists of cryptogams found in 

 special localities. For example, a list of the seaweeds of the New 

 England coast, (published in 1881) "included keys, descriptions, 

 critical notes and plates," and according to Professor Riddle "still 

 remains our only scientific manual of the seaweeds of this region." 



Quite as important as this was the " Provisional Host Index of the 

 Fungi of the United States" published in 1888 and 1890 with Mr. A. 

 B. Seymour, which has proved of the greatest use to working botanists. 



Of his bibliographical papers the most important was a "Biblio- 

 graphic Index to North America Fungi," of which the Introduction 

 and the first 312 pages, prepared in collaboration with Mr. A. B. 



