38 BOTANICAL GAZETTE [roxy 
The basal cell of the axial row develops into the embryo sac. 
Fig. 22 shows a two-celled embryo sac, with the disintegrating remains 
of the other cells of the axial row above it. Immediately after the 
first division of the macrospore nucleus, the two daughter nuclei take 
up a position at opposite poles of the embryo sac, and the cyto- 
plasm becomes more vacuolate. The cells surrounding the develop- 
ing prothallium are large, usually binucleate, and suggest a tapetum, 
as described for Taxodium by Coker (5). The nuclei of the pro- 
thallium divide simultaneously and form an ever-increasing ring of 
free cells (fig. 23). A layer of spongy tissue surrounds this ring and 
separates it from the other cells of the nucellus. By May 30 cell 
walls are laid down between the free nuclei, beginning at the periphery 
and extending toward the center. Contrary to SoxoLowa’s (23) 
generalization for gymnosperms, and Norén’s observations for J. 
communis, cross-walls are formed before the central vacuole has 
entirely disappeared. 
In the upper end of the prothallium a few cells do not divide by 
cross-walls, but remain long and narrow. These are the fundaments 
of the archegonia. By the latter part of May or first of June, the 
nuclei in these cells divide and give rise to the mother cell of the neck 
cells and to the central cell of the archegonium (figs. 24, 25). The 
central cell remains undivided until just before fertilization. Its 
nucleus is in the upper half of the archegonium, and below it is a 
large cylindrical vacuole. The cytoplasm stains faintly, and the 
nucleus contains several nucleoli. As a result of the division of the 
central cell, there arise the egg cell and the ventral canal nucleus. 
As observed by Norén (20) and Stupsky (22) no distinct ventral 
canal cell is ever formed. During the division the cytoplasm stains 
very deeply and presents a most peculiar appearance. Scattered 
throughout the entire cytoplasm are many bodies with deeply staining 
centers which are the so-called protein vacuoles. Three centers of 
radiations are present in the cytoplasm at this time, two below the 
large vacuole and one above it. The radiations appear to have no 
connection with the division of the central cell, but they are never 
seen so clearly at any other time as during this mitosis. Somewhat 
similar radiations are described by Coker (5) for Taxodium. Nor&N 
(19, 20) and Stupsky (22) figure and describe them for Juniperus, 
