The Morphology of Chloranthus. 51 
present in the staminal scales of all three species, and were also 
found in the ovary wall (Fig. 9). 
The youngest spikes of the available material showed the 
flower with its ovary having as yet no indication of ovule apparent. 
Fig. 3 is a median longitudinal section of the flower of C. chinensis 
at this stage. The ovule is first seen as a slight bulge on the 
adaxial side of the ovary wall, which forms a hollow cylinder with a 
very narrow lumen (Fig. 9). The passage or canal of the style is 
lined by a definite layer of small cells. There is no indication of 
integuments, but a number of prominent hypodermal cells are seen 
to have divided by periclinal walls. These cells represent the 
archesporial tissue, and the first division in them separates the 
sporogenous from the tapetal cells (PI. IV., Fig. 14). 
Fig. 15 shows a somewhat older ovule. The outer and inner 
integuments have been developed and the nucellus has increased in 
size and become more distinct. From the inner segments of the 
archesporium a group of cells is developed, distinguished by the 
size of the cells, the size of their nuclei, and their reaction to stain, 
as definitely sporogenous in character. The limits of this group 
are shown in median longitudinal section by narrow elongated cells 
on either side of it. The outer segments, or primary tapetal cells, 
undergo one or more periclinal divisions and over the sporogenous 
tissue form a cap that can be seen even in quite early stages 
(Figs. 15, 19). Shortly after this, periclinal walls form in the 
epidermal cells at the apex of the nucellus (Fig. 16). The inner¬ 
most cells of the central mass within the nucellus become larger in 
size than the others, and have large nuclei. As the nucellus grows 
more bulky, the cells of the whole sporogenous mass increase in 
size, and one of them becomes distinguishable as the mother cell of 
the embryo sac. This is usually the lowest cell of the central 
column of cells in the sporogenous mass (Fig. 15), but in other 
cases a sporogenous cell in a lateral position becomes the mother 
cell. The ovule continues to increase in size, the embryo-sac 
mother-cell becoming most conspicuous by reason of its size and 
very large nucleus (Fig. 17). 
After the embryo-sac mother-cell has attained its full length, it 
undergoes division by approximately transverse walls and forms a 
row of four cells. Of these four cells, usually only one develops 
further and becomes the single embryo sac. Its position in the row 
is by no means constant (Figs. 18, 19,20). There was no indication 
of more than one sporogenous cell undergoing “tetrad” division. 
Several cases have, however, been observed in which two young 
