Studies in the Morphology of Torreya californica.209 
no other ovule have I found any certain trace of a ventral canal- 
nucleus. There is often in the later stages a curiously reticulate 
and fibrous structure, sometimes including small safranin-staining 
bodies, in the protoplasm of the tip of the egg-cell; this may 
possibly be the result of disintegration of the ventral canal-nucleus 
(Fig. 14). 
During the latter half of August the egg-nucleus grows a good 
deal, but its chromatin does not appear to increase, and tends to 
concentrate in the middle of the nucleus. One or more nucleoli are 
present. The rest of the nucleus is filled with a finely granular 
substance. Fig. 14 shews the state of an egg-nucleus early in 
September. When the actual union of the male and female nuclei 
is taking place, the chromatin is againdistributed fairly evenly 
through the egg-nucleus (Fig. 20). The protoplasm of the mature 
archegonium is vacuolated and granular and often contains one or 
more darkly-staining masses near its base (Fig. 20). The presence 
of these deeply staining structures in the protoplasm of the egg-cell 
has been noted in various Conifers e.g. Thuja} 
V.— The Pollen-Tube. 
I have not found any indication of a pollen-chamber in the apex 
of the nucellus. No prothallial cells are produced in the pollen- 
grain, which consists when ripe of two cells, of which presumably 
the smaller is the generative-cell and the larger the tube-cell. The 
youngest pollen-tube which I have been able to observe occurred in 
an ovule whose embryo-sac was eight-nucleate, and here the division 
of the generative-cell had already taken place. A pollen-tube at a 
similar stage is drawn in Fig. 12. Both the body-cell and its nucleus 
increase greatly in size, and Fig. 15 shews the end of a pollen-tube 
from an ovule collected seven weeks later. Here the stalk and 
tube-nuclei are lying closely pressed together in front of the 
body-cell. In later stages only one vegetative nucleus can as a rule 
be recognised in the pollen-tube, and this may be brought about 
either by the fusion of the stalk and tube-nuclei, or by the dis¬ 
appearance of one, probably the tube-nucleus. A pollen-tube at a 
similar state of development to that shewn in Fig. 15 was tested 
for starch, which was found to be present in the protoplasm sur¬ 
rounding the stalk and tube-nuclei, but could not be recognised in 
the dense substance of the body-cell. The protoplasm of the body¬ 
cell at this stage shews slight radiations from a point in front of the 
1 W. J. G. Land. “A Morphological Study of Thuja." Bot. 
Gaz. XXXVI, 1902. 
