1918] The Ottawa Naturalist. 143 



young, which are dependent upon their mothers until the autumn, 

 when they leave the islands with the other seals and fend for them- 

 selves. The young fur-seals cannot swim at birth and do not venture 

 into the water until they are a month or six weeks old.* As the young 

 male seals do not go on the breeding rookeries but "haul out" by 

 themselves they can be driven to the killing-grounds without disturb- 

 ing the breeding seals and it is only these young males that are now 

 killed. 



REVIEW. 



Flora of the Rocky Mountains and Adjacent Plains, 

 containing descriptions of the native and naturalized flowering plants 

 and fernworts, growing in COLORADO, UTAH, WYOMING, 

 IDAHO, MONTANA, SASKATCHEWAN, ALBERTA, and the 

 neighboring parts of NEBRASKA, SOUTH DAKOTA, NORTH 

 DAKOTA and BRITISH COLUMBIA, by P. A. Rydeberg, Ph.D., 

 Curator, New York Botanical Garden. Published by the author. 

 Price S4.05 post free. 



At any time during the last half-century the more eastern Ameri- 

 can botanists have had a handbook or manual by which the could 

 identify the species they collected, but it was not until quite recent 

 years that western botanists had such helps to the study of plants, 

 and the Canadian botanist resident between Manitoba and British 

 Columbia was until a few months ago without a worth-while book of 

 any kind. Even th^ professional botanist with access to a good 

 library was never certain that the species before him had not been 

 described or re-described in some obscure periodical or list that was 

 unknown to him. The average amateur botanist could do nothing 

 but send his difficult species to some large herbarium for determina- 

 tion. Dr. Rydeberg's fine book has changed all this and the fact that 

 it was primarily intended for the United States makes it all the more 

 valuable to Canadian botanists. A flora restricted to the species 

 known to occur in Canada would have left the Canadian botanist 

 without descriptions of scores of species which undoubtedly grow in 

 western Canada but have not yet been recorded. Indeed the writer 

 during the short time he has used the book has noted in the herbarium 

 of the Geological Survey several species that had not been separated 

 from closely allied ones, and of course he will find many others. 



Dr. Rydeberg has been studying the flora of the Rocky Mountain 

 region for more than twenty-five years both in the field and in the 

 herbarium and in the 1110 pages of his Flora he describes 1038 genera 

 and 5897 species of plants. Keys to families, genera and species, 

 make a study of the descriptions unnecessary in the great majority of 



