344 PROCEEDINGS OF THE ACADEMY OF [1884. 



should be added to the above 40*7. The North American species 

 received have been 1792, from tropical America were 3, and from 

 the old world 1388. Among the additions may be specified 1057 

 species, mostly European and North African, from the fine 

 Herbarium of Geo. Curling Joad, presented by Dr. Gray. Though 

 the most of these duplicated species which we already possessed, 

 yet being choice specimens, collected and ticketed by eminent 

 botanists, they greatly add to the value of our working material, 

 while about one-tenth of them were previously unrepresented on 

 our shelves. Our fellow-member, Mr, Canby, who, it will be 

 remembered, was in charge of the Botanical Department of the 

 Northern Transcontinental Survey, during the years 1882 and 

 1883, in the interest of the Northern Pacific R. R., has contributed 

 a very valuable suite of the collections made by himself, and by 

 Scribner, Brandegee, Tweedy and others under his direction, along 

 the northern border of Western North America, in the Territories 

 of Dakota, Montana and Washington. This series comprehends 

 851 distinct species of which about 90 were new to us. Our Vice- 

 Director, Mr. Meehan,has also given us the result of his herbori- 

 zations along the coast of Washington and Alaska Territories, 

 during the summer of 1883, in a collection of 207 species, which, 

 however add only five species to our earlier Alaskan collections 

 received from Kellogg, Harrington, Dall, and others. Other 

 smaller but valuable donations, will be detailed in the Academy's 

 Donation List for 1 884. 



In large collections, where constant accessions, during a long 

 period of years, have repeatedly duplicated species, there is 

 always a tendency to exaggerated estimates of the number of 

 species represented. In regard to the Academy's Herbarium, the 

 estimates have been so vague and so evidentl}' excessive, that the 

 Conservator has been led to undertake an actual enumeration. 

 This apparently simple task is really attended with many diflB- 

 culties, one of which, consists in the varying views of botanists 

 as to the specific validity of forms. In some families this 

 diversity of opinion is so great as to materially affect total 

 results. In such cases, the Conservator has endeavored to 

 follow the authority of the latest leading specialists. Another 

 difficulty arises from the large amount of un worked and unnamed 

 material, which has accumulated since the early days of the 

 Academy, some of it probably duplicating the named species. 



