120 BOTANICAL GAZETTE [FEBRUARY 
in figs. 82-85. Before this last process is completed, the ple- 
rome cells may begin to divide into an inner and an outer layer, 
as seen in the left lower octant of fig. 86. This makes the 
plerome of this region consist of two concentric layers of cells,a 
condition shown again in figs. 89-91. In fig. gr, at the left, the 
outer of these layers is again splitting in two. 
We must now return to the consideration of the cell below the 
octants, in order to discover what it contributes to the embryo. 
Starting with the middle cell of fig. 69, it is easy to trace it, with 
the vesicular cell next to it, through figs. 70-73, 75 and 70. 
This cell, or its product, is labeled ¢ throughout the figures. 
In fig. 74, cell ¢ has divided once, longitudinally. In jig. 75, 
judging by the size of the cells, c is undivided, while the vesicular 
cell has acquired a transverse wall. In this way a varying 
number of suspensor cells may arise. 
The longitudinal wall in cell c, shown in figs. 7g and 77, is 
soon followed by a second one at right angles to the first, giving 
a tier of four cells, three of whose nuclei are shown in fig. 79- 
In figs. 78 and 82, periclinal walls have arisen, cutting off an 
outer dermatogen layer. It will be seen that cell c is undergo- 
ing a series of divisions exactly similar to those arising in the 
lower octants. A second series of periclinal walls, predicted in 
fig. 86, and incomplete in figs. 83 and 88, is completed in fig. 89- 
In figs. 90 and gr, the innermost of these three concentric layers 
has split again longitudinally. 
The claim of an ‘addition to the embryo” from the ‘sus- 
pensor” is not a new one. It will be sufficient to cite from 
two of the more recent papers upon Composite embryology: 
Mottier (20) finds that in Senecio aureus the cell below the 
octants contributes dermatogen and periblem to the embryo, the 
root cap, to judge by his figures, being organized by the next cell. 
He makes no specific statement upon this point. Schwere (24) finds 
two “suspensor”’ cells adding dermatogen and periblem to the 
embryo of Taraxacum, while the third cell organizes the root cap- 
The embryo of Silphium differs from that of Taraxacum in 
that the product of but one original cell lies between the octants 
