REVIEWS . 



Ecological Studies in the Tension Zone Betzveen Prairie and Wood- 

 land. By J. E. Weaver and A. F. Thiel. The Bot. Sur. Nebr.. N. S., 

 No. 1, 60 pp., 38 figs. l!)ir. 



Further Studies in the Ecotone Betzveen Prairie and IVoodland. 

 By R. J. Pool, J. E. Weaver, and F. C. Jean. The Bot. Sur. Nebr., 

 N. S.. No. 2, 4" pp.. IT figs. (This number reprinted from Univ. of 

 Nebr. Studies, Vol. 18, Nos. 1 and 2, l')18.) 



The Botanical Survey of Nebraska, since its organization in 1892 

 by the Botanical Seminar of the University of Nebraska, has made 

 steady progress in the study of the phytogeography of the Stale. Its 

 recent reorganization by a new generation of botanists has marked a 

 new era in which the older methods of the phytogeographer have been 

 replaced by the more exact quantitative methods of the modem 

 ecologist. as is evidenced by two of its latest publications. 



The first monograph under review is based on two years' Vv^ork by 

 Weaver and Thiel in the vicinity of Minneapolis, Minnesota, supple- 

 merited by similar work near Lincoln, Nebraska, and might in a way 

 be considered a sequel to Weaver's work in southeastern Washington 

 and adjacent Idaho. ^ 



Physical factor stations were maintained in the high prairie, low 

 prairie, hazel thicket, oak forest, and hard maple forest, where soil 

 moisture, wind movement, evaporation, temperature, and relative hu- 

 midity were recorded. The transpiration losses per square decimeter 

 of leaf surface were obtained for potted seedlings of bur oak, white 

 elm, silver maple, and green ash. The results showed in everv case 

 a marked decrease in transpiration when the plants were placed in the 

 scrub community. The average loss in the prairie compared with that 

 in the scrub gives the ratio of 100 :53. The ratios of these transpira- 

 tional losses in the scrub and prairie communities were found to vary 

 with the species and with its former environmental condition. In 

 general, the authors found a correlation between the water loss from 

 the plant and the aerial conditions as summed up by the evaporating 



1 Weaver, J. E. A Study of the Vegetation of Southeastern Washington and 

 Adjacent Idaho. Univ. Nebr. Studies XVII, No. 1, 1917. 



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