ECOLOGY. 319 



lost but 15.55 pounds. Wheat-grass, Agropyrum glaucum, transpired 90 per 

 cent as much as millet, and lowland prairie sod at Lincoln 80 per cent as 

 much as alfalfa. When the much longer period of growth is taken into 

 account, it is evident that the native grasses lose as much water in the growing 

 season as the ordinary crops, with the possible exception of corn. More 

 significant, however, is the fact that even the short-grasses transpire more 

 water in a season than the annual rainfall at Phillipsburg or Burlington, 

 while the loss from bluestem is approximately twice the annual rainfall. 



Methods and Principles in Palceo-ecology , by F. E. Clements and R. W. Chaney. 



The preliminary organization of the new field of palseo-ecology, outlined 

 in Plant Succession (1916) and Scope and Significance of Paleo-ecology (1918), 

 has been tested and expanded by the application of the methods and principles 

 to the fossil flora of the John Day Basin. This has involved the trial of the 

 basic methods of quantitative and developmental ecology as exemplified in 

 association, succession, phylogeny, climatic cycles, migration, and adaptation 

 especially, and this has progressed far enough to show that the fossil material 

 in many formations is adequate for far-reaching reconstruction, when suffi- 

 ciently refined and utilized in accordance with proper ecological principles. In 

 this connection it has proved imperative to check all the evidence drawn from 

 leaf-impressions, by means of wood sections and fruits so far as the latter are 

 available, but especially to make use of the range of variation as shown by 

 modern plants of the same or related genera and species. This has fully 

 confirmed the original working hypothesis derived from the principles of 

 climatic cycles and association (Plant Succession, p. 362), namely, that modern 

 species appeared much earlier in the Tertiary than has been supposed and that 

 tropical genera could not be expected to thrive in the same climaxes as 

 temperate or boreal ones. It also lends further support to the view that 

 climatic climaxes were differentiated on the North American continent 

 during the early Mesozoic and that in the Tertiary they closely resembled 

 those of to-day in character if not in extent. The hypothesis which links 

 the origin of Angiosperms with Permian climatic cycles and regards the 

 highest types, the grasses, oaks, etc., as evolved by similar changes during 

 the Mesozoic, is placed on a correspondingly firmer basis. In conformity 

 with rapidly accumulating evidence as to the present, migration in the past 

 appears to have been primarily a response to the alternating phases of climatic 

 cycles, the climaxes expanding or contracting with wet and dry phases but 

 never disappearing. A progressive but slow differentiation of species went 

 with this, nicely illustrated by the fact that Miocene and Oligocene forms of 

 widespread boreal species usually resemble Eurasian subspecies more than 

 American, 



Biotic Succession in Bad Lands, by F. E. Clements. 



The usual number of bad-land regions have been examined during the year, 

 extending from Arizona to Oregon and from California to Texas, and ranging 

 in time from the Permian to the Pleistocene. In California the chief forma- 

 tions were the Miocene of Death Valley, the Monterey, and Fernando; in 

 Oregon and Idaho, the Payette; in Wyoming, the Laramie, Wasatch, Bridger, 

 and Green River; in Colorado, the Pawnee Creek; in Nebraska, the Brule; 

 in Texas, the Permian; and in Arizona, the Pliocene and Pleistocene. Atten- 

 tion was focused primarily on present-day succession in these areas and the 

 relation of this and erosion to the existing climatic cycles. Along the northern 



