﻿BOTANICAL GAZETTE 



I XI-I.W ATIOX OF PLATE XIII 

 ngitudinal sections through the bases < 



Fig. 5.— A small portion of the separation layer in the cortex in which 

 abscission is complete; the abscission cells are more or less distorted, but 

 those in the middle of the figure but little, and in these the normal nuclei can 

 be seen; 3 cloudy masses can here be seen, and these are shown on a larger 

 scale in fig. 6. 



Fig. 6.— Longitudinal walls in a swelled and partly hydrolyzed condition; 



compare with figs. 1 1 -13. 



Fig. 7.— Abscission cells in the pith, when separation is readily possible; 

 on the left of the central cell, the altered cell wall has broken, the tertiary 

 membranes alone remaining intact; the protoplasm and nucleus are clearly 



Fig. 8.— The intact membranes of abscission cells remaining after sepa- 

 ration has been procured; this preparation was secured by pulling apart a 

 section such as that in fig. 5 ; at the free ends of the cells the membranes are 

 seen to be somewhat thicker (cf. text fig. 1, d). 



reduced staining capacity of the walls of the cells proceeding toward abscission; 



drawn out; there is further shown the transfer of the abscission plane from 

 one cell tier to another; small, relatively unaltered portions of cell walls are 

 seen suspended by the thin membranes. 



Fig. 11— Between the two protoplasts may be seen an oval intercellular 

 space inclosed by two delicate tertiary membranes; these have been set free by 

 the complete hydrolyzation of the remainder of the wall, of which nothing 



Fig. 12.— Medullary ray cells in abscission, in which the cell walls are 

 hydrolyzed so far that they now appear granular or flocculated; only the wall 

 in the center of the figure shows this well; this has been further magnified and 



of the altered cell wall ; ruthenium red. 



