

Cook : Potamogeton lucens 217 



Summary 



1. The formation of the embryo is regular and typical. 



2. The primary endosperm-nucleus divides and the two 

 daughter-nuclei are separated by a wall. The one in the synergid 

 end of the sac gives rise to the endosperm while the one in the 

 antipodal end grows rapidly, is very active, and moves downward 

 into an extension of the sac formed by the disintegration of the 

 nucellar tissue, where it finally undergoes disintegration. 



3. The endosperm is conspicuous, usually parietal and nuclear, 

 without cell-walls. 



4. The embryo follows the Alisma type in its development. 



O LlTERATUE 



Development of the embryo-sac and embryo of 



1. Campbell, D. H. A morphological study of Naias and Zannichel- 



lia. Proc. Calif. Acad. Sci. III. 1 : 1-62. //. 1-5. 1897. 



2 - • Studies on the flower and embryo of Sparganium. Proc. 



Calif. Acad. Sci. III. I : 293-328. //. 46-48. 1897. 



3. Coker, W. C. The development of the seed in the Pontederiaceae. 



Bot. Gaz. 44: 293-301. //. 23. 1907. 



4. Cook, M. T. 



Castalia odorata and Nymphaea advena. Bull. Torrey Club 29 : 

 211-220. //. 12, 13. 1902. 



5- • The embryology of some Cuban Nymphaeaceae. Bot. Gaz. 



4 2 = 376-392. //. 16-18. 1906. 



6> " • The embryology of Sagittaria lancifolia L. Ohio Nat. 7 : 



97-101. pL 8. 1907. 



7- Coulter, J. M. & Chamberlain, C. J. Morphology of the Angio- 



sperms. T903. 



8. Hall, J. G. An embryological study of Limnocharis emarginata. 



Bot. Gaz. 33: 214-219. pi, 19. 1902. 

 9- Holferty, G. M. Ovules and embryo of Potamogeton natans. 



Bot. Gaz. 31 : 339-346. //. 2, 3. 1 90 1. 

 1o - Johnson, D. S. On the development of Sail runts cernuus. Bull. 



Torrey Club 27 : 365-372. pi. 23. 1900. 



On the development of certain Piperaceae. Bot. Gaz. 34 : 

 321-340. pi. p f /o. 1902. 



1 2 - Schaffner, J. H. The embryo-sac of Alisma Plantago. Bot. Gaz. 



21 : J 2 3-i3 2 • pi- 9, 10. 1896. 



11. 



