BOTANY: I. W. BAILEY 
Proc. N. a. S. 
plate, leaving a ring-shaped aggregation of kinoplasmic fibers, which in 
tangential longitudinal sections of the cambium appears as a halo about 
the daughter nuclei, figure C. This ring increases in circumference until 
it intersects the radial walls, when it becomes more or less flattened on 
two sides. As soon as the cell plate intersects the radial walls of the 
cell, the fibers in these two sides disappear leaving two separate aggre- 
gations of kinoplasmic fibers which are connected by the cell plate, figures 
E, F, G, H. These aggregations of fibers, kinoplasmasomes, have the 
same characteristic shape and structure as those which occur in the Coni- 
fer ae. They extend across the cell — more or less at right angles to its 
longitudinal axis — from one radial wall to the other, figure G, and are 
Rohinia Pseudo- Acacia L. 
k 
1, 
k 
n 
k 
A 
B 
71 
k 
n 
1 
k 
k 
c 
D 
A. Central portion of cambial initial, in tangential longitudinal extension, showing 
early "disk" stage in the formation of the cell plate. X 900. 
B. The same. Radial longitudinal extension. X 900. 
C. Central portion of cambial initial, in tangential longitudinal extension, showing 
"ring" or "halo" stage in the formation of the cell plate. X 900. 
D. The same. Radial longitudinal extension. X 900. 
located in the center of the protoplast, midway between its tangential 
surfaces, figure H. They move in opposite directions — usually at equal 
rates — towards the ends of the cell. As they move forward, the cell 
plate is extended until it eventually reaches the two ends of the protoplast, 
thus dividing it into halves, each of which contains one of the daughter 
nuclei. The latter usually remain close together near the center of the 
cell during cytokinesis, as in the gymnosperms; and I have been unable 
to find any visible connection between them and the kinoplasmasomes. 
Having determined that this type of cytokinesis is characteristic of 
the cambia of both gymnosperms and angiosperms, it is of interest to in- 
