246 Transactions of the Royal Society of South Africa. 
to the latter there is some doubt as to whether the multinucleate structures 
descril:)ed and figured are proembryos.* Coulter describes the proembryos 
of G. Gnemon;f as many as four free nuclei were observed. We find in 
G. africanum from two (Plate L, fig. 27) to five (Plate L, fig. 28) ; our 
material has not furnished any later stages. Coulter gives some further 
information regarding these, and Bower :j: has described the development of 
the embryo ; there is, however, much yet to be learned about both. 
Summary. 
1. Nucellus and Pollen- chamber. 
A disintegration of the nucellar cap tissue, in general similar to that 
described for G. Gnemon, frequently occurs also in G. africanum. It does 
not appear to interfere in any way with the functions of the ovule. 
The form of the pollen-chamber appears to be a specific character. 
The pollen-chamber of G. africanum often becomes partially filled by 
papilla-like cells growing down from the tissue blocking the micropyle. 
2. The Pollen-tube and Sperm-cell. 
In G. Gnemon and G. africanum the pollen-grains in the micropyle con- 
tain two or three free nuclei. If three are present, one does not enter the 
pollen-tube. The last is identified as the prothallial nucleus which, in the 
case of the 2-nucleate grains, has disappeared before pollination. 
In G. africanum the generative cell is organised soon after the beginning 
of germination. Later, this cell becomes binucleate ; the two nuclei are 
unequal ; it is probable that sometimes one of them disappears before the 
pollen-tube reaches the embryo-sac. Earely the protoplasm of the cell 
breaks into two uninucleate portions. The tube nucleus, usually smaller 
than the generative nucleus, usually disappears before the growth of the 
pollen-tube is completed. The first division of the generative cell into 
*' body " cell and " stalk " cell is eliminated. 
3. Embryo-sac and Endosperm. 
The Mitoses in a free nuclear stage in G. africanum are simultaneous. 
The pollen- tube reaches the top of the embryo- sac before or at any time 
after the beginning and before the completion of endosperm formation. 
There is reason to believe that this is also true for other species. 
Endosperm is formed in the micropyle region of the sac in precisely the 
same manner as at the chalazal end, except that the processes of septation 
and nuclear fusion at any point may be interfered with by the activities of 
a pollen-tube or oospore. Under such circumstances a few of the sac- 
* Cf. Lotsy, 1911, p. 352. 
t Coulter, 1908, p. 46, figs. 6, 7. 
X Bower, 1882. 
