lO ROYAL SOCIETY OF CANADA 



these works and their successors — more particularly those dealing with 

 the mosses and lichens — for our general knowledge of the plants with 

 which they deal. 



This period was, nevertheless, notable for two events of more than 

 ordinary significance. In 1836, the results already reached by Arctic 

 exploration were then enlai-ged by the observations and collections ob- 

 tained during the expedition of Sir George Back to the mouth of the 

 Great Fish River. In these results wo observe for the first time a serious 

 attempt to extend the botanical work beyond the mere collection of 

 plants, and in his pha?no]ogical observations, especially those relating to 

 the teniperatui-e of trees, Sir George Back indicated some of the more im- 

 portant directions in which such scientific work should be prosecuted. 



In 1840 the Flora Boreali Americana made its appearance. In this 

 ver}' important work Sir William Hooker presented a complete summary 

 of all the results derived from the numerous Arctic and other explora- 

 tions which had taken place during the preceding thirty years. It was, 

 therefore, at that time, a complete summary of our knowledge of the 

 Canadian flora, and it represents for that time what has been accom- 

 plished more recently in a more extended, though dilFerent Avay, by 

 Macoun's Catalogue, it is, in fact, one of the most important of the few 

 landmarks which indicate the various steps in the progress of Canadian 

 botany. 



Wiih the exception of Hooker and Back, this period is notable for 

 the absence of local work and our almost complete dependence upon that 

 of American investigators ; and we thus find the names of Ratinesque, 

 Gray, Torrey, Tuckermann and Siillivant standing forth with great pro- 

 minence as exerting a dominant infiuence. The New Flora of North 

 America, which Rafinesque issued in 183G, was intended to be an enlai'ge- 

 ment upon the work of his predecessoi-s — that it should, in fact, supplant 

 and be additional to all the botanical works hitherto published in JSorth 

 America and the United States. 



Torrey had already contributed in important ways to a knowledge 

 of our flora, but in the Genera of North American Plants, his studies of 

 the Cyperaceai and more particularly in his Flora which was issued as a 

 joint work with Dr. Gray, he added very materially to our knowledge. 

 Gray, who was later to exert an important influence upon Canadian 

 botany through his numerous publications, was, during this period, brought 

 into close sympathy with scientific progress in Canada not only through 

 his joint work with Toi-rey, but through his later publication of the 

 Genera of North American Plants. 



To Tuckermann we are indebted for the first and most complete study 

 of the North American Lichens, a work which extended from 1845 when 

 his first enumeration appeared, until 1882, the date of the publication of 

 his last ettorts. Although Tuckermann's descriptions are usually so 



