26 BOTANICAL GAZETTE (juLy 
these cells increase somewhat in size until they are noticeably a 
larger than those of the surrounding tissue, but unlike the 
sporogenous nuclei remain very dense. As the embryo-sac 4 
grows larger these cells are all pushed aside, with the exception — 
of the more central ones which persist between the embryo-sac 
and the epidermis until after fertilization. : 
The other daughter cell resulting from the division of the 
primary hypodermal cell constitutes the archesporium. This E 
immediately expands in all directions, partly at the expense of 
the ordinary tissue. At the time of the first nuclear division, 
the cell is oblong in shape and occupies a considerable portion 4 
of the nucellus. The nucleus during its period of growth passes 
through stages almost identical with those described for the — 
microsporangial archesporium.t The chromatin network changes _ 
during synapsis (fig. 2) to a spirem ribbon (fig. 3), which later 
segments into the individual chromosomes. Corresponding — 
Stages in the nucleus of the pollen-mother cells and embryo-sa¢ 
archesporium cannot be distinguished structurally; and this 
similarity is still farther emphasized by the synapsis occurring 
in each at the same stage in development. af 
lh Si 
THE FIRST NUCLEAR DIVISION. 
Several good preparations of the first nuclear division we 
obtained, both in the nuclear plate and anaphase stages. In th 
plate stage the fibers are well marked; indeed the fascicles 
attached to the chromosomes are especially large and prominent 
The spindle, like that of the pollen-mother cell, is rarely po 
at the poles, but is more often truncate (fig. 4 
The chromosomes are large oblong bodies arranged on the 
nuclear plate just as they are in the pollen-mother cell ; that 
horizontally with one end directed away from the axis. Simul 
taneously the outer and inner ends commence to split longitu 
dinally, but in perpendicular planes. In one case the page 
is ors a wholly without the aid of the spindle fibers; 
* WIEGAND: The development of the microsporangium and microspores in Com 
vallaria and kaa Bot. GAZ, 28: 328. 1899. 
