58 



scattered sources, and the wonder is that the need for such a 

 book in agricultural colleges was not met several years ago. 



C. Stuart Gager. 



Weaver's Study of the Vegetation of Southeastern Washington and Adjacent Idaho; 



and Ecological Studies in the Tension Zone between Prairie 



and Woodland, by Weaver and Thiel 



After thirteen years of quiescence, a notable series of publica- 

 tions of the Botanical Seminar of the University of Nebraska has 

 been revived by a new generation of ecologists and phytogeogra- 

 phers. The second paper noted above is number one of the new 

 series of "Botanical Survey of Nebraska," the last of the old 

 series being published in 1900 as the second edition of "Phyto- 

 geography of Nebraska I," originally issued in 1898. 



Considering the last paper first, the authors show that in the 

 tension zone between forest and prairie the lack of available 

 water and high transpiration on the latter explains the failure of 

 the trees to encroach seriously over the prairies, except in gullies 

 and other favorable places where there is water. A system of 

 records showing available water supply and transpiration, and the 

 reflection of these factors in the vegetation itself, are described 

 in detail, the whole paper covering 60 pages, with numerous 

 pictures, tables and graphs to illustrate the points discussed. 

 In this connection some of the conclusions of Gleason, Harper, 

 Shimek and others should be studied by those who may not be 

 inclined to ascribe as much importance to water as the authors 

 of the paper under discussion evidently do. They make scarcely 

 any mention of fire as a factor, whereas some writers consider it 

 almost the factor. They promise, however, to carry out a series 

 of "carefully planned quadrat studies" to answer the question 

 " Can trees grow from seed sown in the prairie or worked into the 

 surface soil and under what conditions?" 



The other paper by Dr. Weaver is a pamphlet of 133 pages and 

 48 illustrations, and is a systematic description of the vegetation 

 of southeastern Washington and eastern Idaho. That such a 

 region contains vegetation described under prairie-plains for- 

 mation, desert-scrub formation, Pacific coast forest formation, 

 Hydrosere, etc., bears out the author's statement that the area 



