1914] CURRENT LITERATURE 281 



devised by Briggs and Shantz to express the wilting coefficient in terms of 

 soil composition is capable of simple modification for higher rates of transpira- 

 tion. As there seems to be no reason at all to doubt the experimental accuracy 

 of the work of Briggs and Shantz, especially when their extensive character 

 is taken into consideration, the second of these problems would seem to offer a 

 favorable field for further experimentation, with a strong probability of results 

 that would be useful in many phases of ecological study. Indeed, the most 

 recent paper upon the subject by Shive and Livingston 5 makes an unsuccessful 

 attempt at a determination of the limits within which the formula of Briggs 

 and Shantz does apply. It confirms the results of Caldwell, further empha- 

 sis being given to the fact that for the soils of high water-holding powers the 

 wilting coefficient, or the "soil moisture residue at permanent wilting" as 

 Shive and Livingston prefer to call it, even with high evaporating power of 

 the air, is but little above, in fact, in some instances, is slightly below that 

 obtained by the direct methods of Briggs and Shantz. This paper also con- 

 tains an attempt to express by an algebraic equation the relation of the wilting 

 coefficient to the evaporation intensity under which wilting was brought about , 

 but the results are so diverse that only a rather wide approximation is obtained. 

 The general conclusion seems to be that the formula of Briggs and Shantz 

 holds within certain limits, as yet undetermined, but doubtless within atmos- 

 pheric conditions of comparatively low evaporation intensity. — Geo. D. 

 Fuller. 



Ecology of fresh-water algae. — Comere 6 has published a general account 

 of the ecology of the fresh-water algae. The paper itself is so nearly a summary 

 of the results of investigations by the author and other European limnologists, 

 that it is difficult to condense the matter further. The paper is divided in 

 three parts, the first of which considers the classification and nomenclature of 

 aquatic formations, the separation of these formations into characteristic 

 regions, and the arrangement and terminology of the "florules" corresponding 

 to these regions. This part is especially useful because of its concise definitions 

 and citations of synonyms. Algal habitats are primarily divided into aquatic 

 and subaerial. The former are further separated into permanent and tran- 

 sient groups. The algal formations are first divided into those of large lakes, 

 small lakes, and streams. In these there may be further recognized the littoral, 

 planctonic, and bottom regions, each with its corresponding florule. The sub- 

 divisions are too numerous to mention here, but this will suffice to show that 



5 Shive, J. \\\, and Livingston, B. E., The relation of atmospheric evaporating 

 power to soil moisture content at permanent wilting in plants. Plant World/7:8i- 121. 

 1914. 



6 Cohere, Joseph, De Taction du milieu consideree dans ses rapports avec la 



distribution generate des Algues d'eau douce. Mem. 25, Bull. Soc. Bot. France 16: 

 i~96. 1913. 



