193 



i893> which has received practically universal acceptance among 

 American botanists. The bibliography, as a whole, however, 

 will be invaluable to future students, in that it brings together, 

 in one place, and for the first time, most of the important books 

 and articles that have been printed, thereby making it possible 

 to get bibliographic information on any given subject almost at a 

 glance. 



II. Geographic, Climatic and Floristic Survey. The first 

 chapter of this part is a brief (pp. 93-130) geographical descrip- 

 tion of the continent and need not detain us, as it is necessarily 

 a compilation from such authorities as Tarr, C. W. Hayes, J. W. 

 Powell, Adams, Wright, R. T. Hill, Keane, and some of the 

 publications of the Bureau of American Republics. The essay 

 draws attention to all the more important physiographic features 

 of our varied topography, and especially to those that have or 

 have had a bearing on the distribution of American plants. 



The selection of material for the second chapter on the climate 

 of North America (pp. 130-165) presents some interesting side- 

 lights on the author's point of view, and his conception of what 

 are the chief climatic factors in the distribution of plants. After 

 a rehearsal of the main climatic features and of some of the general 

 principles of climatology, the book takes up the continental divi- 

 sions in more detail. This is elaborated mostly from the reports 

 of the United States Weather Bureau, and is as comprehensive, 

 along certain lines, as the most critical could desire. The thing 

 that strikes the curious note is the absolute failure to record any 

 of the conclusions of Abbe on the relation between climate and 

 crops, published in 1905, and which have revolutionized our 

 ideas as to the effects of temperature on plant distribution. That 

 maximum and minimum temperature, and that any method of 

 reckoning accumulative temperature or heat units, are not the 

 vital factors in this problem, has been discussed at length in 

 numerous papers within the last three or four years. And the 

 almost general consensus of opinion that tke length of the growing 

 season is the most important factor seems to have escaped the 

 writer's notice. This is much to be regretted, as charts or tables 

 for small areas, such as those in recent papers by Shreve, Gleason, 



