1920] CURRENT LITERATURE 533 



Anatomy of strand plants. — The eastern shore of Madagascar, charac- 

 terized by uniformly high temperature, constant winds, and considerable rain- 

 fall, has as its principal strand communities two associations characterized 

 respectively by Ipotnea Pes-caprae and Barringtonia. The plants of the 

 former have been examined by Denis, 7 who finds them, thus exposed to con- 

 ditions of high transpiration, induced by great insolation and rapid air move- 

 ment, almost without any special development of epidermal protection, but 

 possessing varying degrees of fleshiness with water-storing tissue rather well 

 developed. One group shows isolateral fleshy structure with the water tissue 

 centrally placed, another possesses bifacial leaves, less fleshiness, and periph- 

 eral water tissue. These structural tendencies toward fleshiness are related 

 by the author to the saline character of the beach; the development of water- 

 storing tissue and the early lignification of the roots to the high rate of trans- 

 piration ; and the abundance of palisade tissue to brilliancy of both the direct 

 and the reflected sunlight. The details of structure are given in the text and 

 in the drawings of leaf sections. — Geo. D. Fuller. 



Snow and timber line. — From studies made in the Pyrenees, Bouget* 

 has reached conclusions regarding the influence of snow upon alpine and sub- 

 alpine vegetation not unlike those of Shaw 9 from a study of the Selkirks 

 more than a decade ago. In the higher altitudes the duration of the snow is 

 related to the local topographic relief, and its persistence during the growing 

 season profoundly influences the character of the vegetation. In depressions 

 it collects during the winter and remaining late in the season gives rise to a 

 rather mesophytic herbaceous community consisting of a mixture of lowland 

 and alpine forms. In contrast, the relative absence of snow upon the ridges and 

 at the same altitude produces a xerophytic vegetation in which trees and woody 

 plants are conspicuous. Thus the upper limit of trees or timber line is much 

 higher upon ridges than along depressions. — Geo. D. Fuller. 



Action of enzymes on cellulose. — Pringsheim and Magnus-von 

 Merkatz 10 point out that dextrines from both starch and glycogen are split 



I 



to maltose by diastase. They raise the question whether diastase has a 

 similar effect on cellulose dextrine. By using Madsen's acetylization method 

 they gained cellulose dextrine from cotton that was soluble in water and 



1 Denis, Marcel, Recherches anatomiques sur quelques plantes littorales de 

 Madagascar. Rev. G6n. Botanique 31:33-52, 115-120, 129-142. pi. 1. figs. 12. 1919. 



8 Bouget, J., De Tinfluence des neiges sur la r6partition des differents v6g£taux 

 a mene altitude dans les fcones elev6es des Pyr6n6es. Rev. Gen. Bot. 30:305-320. 

 1918. 



* Shaw, C. H., The causes of timber line on mountains; the rdle of snow. Plant 



169- 



Fermentv 



lulose abbauprodukten. Hoppe-Seyler Zeit 



