483 
S tiles . — The Podoccirpeae. 
prothallus. Here they expand in a remarkable manner so as to cover 
almost completely the upper region of the prothallus. From this expanded 
portion branches grow down in all directions (PL XLVIII, Fig. 27). The 
pollen-tube wall is rather thick, about twice as thick in fact as the megaspore 
membrane. At this stage wall formation was taking place in the female 
prothallus. 
The body-cell is a conspicuous object, consisting of a dense mass of 
cytoplasm containing a large nucleus. As described for P. coriaceus ? and as 
is also the case in P. nagi , the nucleolus is the only part which shows any 
marked tendency to take the safranin stain. The nucleus at this stage was 
always excentrically placed in the cytoplasm. The cell itself is not neces- 
sarily spherical ; in one case it was conical, with the nucleus at the base of the 
cone, and giving the impression of a moving cell with the nucleus in front. 
Small nuclei are found in the tube— in one case they numbered five — 
while a mass in the pollen-grain staining densely with safranin suggests 
that some nuclei never leave the grain and disorganize there. No distinction 
could be made out between the prothallial, stalk-, and tube-nuclei ; all the 
small nuclei in the tube appeared similar. Sometimes two or three of these 
small nuclei were clustered near the body-cell, as was found in the 
observed cases of P. nagi ; but this was not always the case, for sometimes 
the body-cell was quite by itself. At this stage the body-cell is of 
considerable size. 
No further change is noticeable in the gametophyte until the division 
of the body-cell. This evidently took place about July 20, for in one ovule 
collected on this date, of four pollen-tubes which had penetrated the nucelltis, 
one contained an undivided body-cell, while in each of the other three the 
body-cell had undergone division. Here, as described for P. coriaceus? the 
division of the body-cell results in the formation of two unequal male nuclei 
(PI. XLVIII, Figs. 28, 29, 31). The functional one is found embedded in the 
middle of the body-cell cytoplasm ; the other moves, apparently in a very 
short space of time, to the side of the cytoplasm, and often that side remote 
from the female prothallus. The functional male nucleus takes deeply the 
safranin or haematoxylin stain, being in this respect in marked contrast to 
the body-cell nucleus. The non-functional male nucleus gradually under- 
goes degeneration. Several ovules showed very prettily the male nuclei 
just outside an archegonium (Fig. 31). The functional male is still em- 
bedded in the middle of the body-cell cytoplasm, while the degenerate male 
nucleus is still obvious. In all cases observed at this stage it was remark- 
able that small nuclei, sometimes as many as six in number, were always 
observed clustered against the body-cell (PI. XLVIII, Figs. 29 and 30). 
Whether they are the original prothallial, stalk-, and tube-nuclei, or whether 
some of these degenerate, while others in the neighbourhood survive and 
1 Coker (’02), p. 95. 2 1. c. 
