80 BOTANICAL GAZETTE 
brane originates either from the inner integument or from the nucellus. 
shown that water and the solutes capable of entering do so mainly through 
the 
if alcohol is added to its water solution. Ether renders the coat more readily 
permeable to water, while treatment with osmic acid renders it less so. While 
this membrane, being of the non-protoplasmic type, is of great theoretical 
interest, it has not been demonstrated of any biological significance to the seed 
itself. In these cultivated forms it is probable that, if such a significance 
existed, it has been eliminated by selection. A study of this membrane in wild 
grasses might prove of interest. Many of the wild forms show delayed germi- 
nation, and in one at least, wild oats, rupturing the coat overcomes the delay.— 
WILLIAM CROCKER. 
Leaf-fall—The phenomena accompanying the process of defoliation have 
been investigated by LEE” in nearly 50 species of trees and woody plants. 
e separation layer is formed from existing cells, with or without division, 
and cuts off the leaf by the degeneration and disappearance of the middle 
lamellae of the cells involved. The vascular elements are ruptured, but usually 
only after tyloses have filled them. The character of the invariably present 
protective layer is made the basis of classification, and the species studied are 
segregated according to whether the ligno-suberized protective cells arise 
(x) without further modification from existing cells; (2) after irregular division 
of existing cells; or (3) from a regularly active cambium. Whether the ligno- 
suberization comes before or after defoliation leads to subdivisions of the first 
two classes. The production of a cork layer continuous with the periderm 
of the stem usually follows in the growing season succeeding defoliation.— 
Gro, D. FULLER. 
» LEE, E., The morphology of leaf-fall. Annals of Botany 25:51—106. I9II. 
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