BOT.— Vol. I.] CAMPBELL— MAIAS AND ZANiYICHELLL4. 53 



pedicels of the flowers was demonstrated, contrary to the 

 conclusions of Magnus with reference to all species de- 

 scribed by him. 



3. The anther of N. jiexilis is regularly unilocular, but 

 not infrequently shows traces of a division into two loculi, 

 which occasionally may be complete. 



4. The large pollen-spores contain at maturity three nu- 

 clei, one vegetative and two generative. The early growth 

 of the pollen-tube is entirely at the expense of the starch 

 in the spore; only after it has penetrated into the ovary is 

 it nourished by the cells of the pistil. In the ovary there 

 are secretory papillae at the opening of the canal of the 

 style and also at the base of the funiculus. 



5. Fertilization is of the usual type. 



6. The first division of the embryo is transverse and 

 divides it into two cells, suspensor and embryo cell. The 

 former remains permanently undivided. 



7. The embryo cell divides by transverse walls into a 

 series of segments of which the terminal one forms the 

 cotyledon; the second, the stem; the third and fourth, the 

 root; the others, the secondary suspensor cells. No root- 

 cap is present. 



8. It is doubtful whether there is always a fusion of the 

 polar nuclei. There is always present subsequently a single 

 large nucleus at the base of the embryo-sac, which may 

 perhaps represent the unchanged lower polar nucleus. Sec- 

 ondary endosperm nuclei are all derived from the upper of 

 the two primary endosperm nuclei. The endosperm is ru- 

 dimentary. 



9. Deviations from the normal type of embryo-sac were 

 noted in several cases. 



B. — Zannichellia. 



1. The anthers and ovules of Zannichellia like those of 

 Naias are strictly axial structures. 



2. The female infloresence is formed by the dichotomy 

 of the main axis, but is not, as has been claimed, the 



