18 BOTANICAL GAZETTE [JANUARY 
2, Four megaspores are usually formed; six were noted in one 
instance. 
3. The embryo sac early develops a pouch in which the antip- 
odal group of nuclei is formed. 
4. The polars approach one another at an early stage and may 
remain for a long time side by side; their fusion, however, was 
not noted before fertilization. 
5. The stamens regularly produce two sporangia each. The 
primary wall layer nearly invests the sporogenous tissue, which 
later may contribute to the tapetum on the axial side. 
6.. The pollen grains adhere in tetrads and have a greater 
specific gravity than water. The exine possesses spines which 
hold back the surface film and imprison sufficient air to keep the 
spores afloat. 
7. The male cells are organized in the pollen grain and are 
joined together by their elongated ends. 
8. Gas bubbles aid in detaching the staminate flowers and in 
bringing them promptly to the surface of the water. 
g. The pistillate flower is impervious to water and so produces 
a depression in the surface film. Pollen grains floating near are 
brought into contact with the stigmas by means of gravity oper- 
ating through the declined surface film. 
10. The large pollen tubes, having penetrated the long floral 
tube, pass directly through the ovarian cavity to the upturned 
micropyles of the ovules. 
11. Pollen tubes which have failed to enter ovules often swell 
up into cyst-like enlargements in the ovary. In these cystoids 
the male structures can be seen as ciate cells instead of nuclei 
only. 
12. Fertilization takes place in the usual manner, and the sec- 
ond male cell was found uniting with the endosperm nucleus. 
13. The primary endosperm nucleus does not divide until a 
two-celled embryo is established. 
14. The Pete tubes — until the embryos are well 
developed. 
15. The suspensor cell of the embryo becomes enormously 
enlarged and the synergid often increases in size. The primary 
