﻿1903J CURRENT LITERATURE 141 



charid nature. The larger granules in the interior of the cells are composed 

 largely of polysaccharid and contain considerable tannin. — Burton E. Liv- 

 ingston. 



T. J. and M. F. L. Fitzpatrick^ give a short account of the genetic 

 development of the island vegetation of the Mississippi river near Sabula, 

 Iowa. The characteristic species associated with the willow-cottonwood-elm 

 society are listed and the significance of certain tendencies indicated. — 



J. M. Westgate. 



r 



HusEK* finds the grains in the root-cap of Allium Cepa to be the 

 so-called "red starch;*' beside amylodextrin they contain a little real starch 

 and some dextrin. The red starch is formed only at ordinary temperatures. 

 The amyloplasts are confined to the root-cap. If the tip is removed, they 

 occur in the regenerated tip. They are formed there de novo from the 

 cytoplasm in Allium. — E. B. Copeland, 



t 



GuiGNARD^ has just reported double fertilization among the Cruciferae. 

 The forms studied were Capsella Bursa-pastoris and Lepidium sativum^ 

 which prove to be almost identical in their main features. The polar nuclei 

 fuse late, just before the entrance of the tube, the fusion-nucleus lying very 

 close to the oosphere. The male cells are small and ovoid, and after dis- 

 charge from the tube pass so rapidly to the oosphere and the fusion-nucleus 

 as not to be caught in the preparations during their passage. The fusion of 

 the male cell with the endosperm nucleus is very much more rapid than the 

 fusion of its mate with the ^%^. It seems to be more and more evident that 

 the so-called double fertilization is a very general phenomenon among angio- 

 sperms.-J. M. C. 



Y 



Breuner^ has made an ecological study of the oak leaves of the world, 

 as to their general adaptations to their native climates. His work includes 

 a study of cultivated or herbarium material from all lands where oaks grow, 

 and some experiments upon living material to show the influence of illumina- 

 tion upon the size, form, and structure of the leaves. Except for the exces- 

 sive individual variability of oak leaves, the genus is a most favorable one 

 for such work. The results of experiments, and of local differences in 

 environment correspond to the specific characters in the climates imitated; 

 whence Breuner concludes "that the modifications in plants called forth by 

 external causes become hereditable, and in the course of evolution may 

 develop into specific characters."— E. B. Copeland. 



SFiTZPATRiCK, T. J. and M. F, L., A study of the island flora of the Mississippi 

 river near Sabula, Iowa. Plant World 5 : 198-201. 1902. 



*HusEK, G., Ueber Starkekorner in den Wurzelhauben von Allium Cepa, 

 Reprint, Sitzber. K. Bohm. Gesells. Wissens. IQ02. 10 pp. 



^GuiGNARD, L., La double fecondation chez las Cruciferes. Jour. Botanique 

 16:361-368./^^. 20, 1902. 



® Breuner W., Klima und Blatt bei der Gattung Quercus. Flora 90: 1 14-160. 

 1902. 



