\ 



258 BOTANICAL GAZETTE [october 



Stages of the embryo, especially in cross sections {^fig* 28). 

 The line of division disappears as the embryo becomes older. 



My acknowledgments are due to Professor John M, Coulter, 

 and Dr. Charles J. Chamberlain for assistance rendered during 

 the progress of the work. 



The University of Chicago. 



LITERATURE CITED. 



t. Arnoldi, W., Embryogenie von Cephalotaxus Fortunez, (Beitrage 

 zur Morph. des Gym. III.) Flora 87: 46-63. //5. /-j. 1900. 



2. Ueber die Corpuscula und Pollenschlauche bei Sequoia 



$empervirens, (Beitrage zur Morph. des Gym. II.) Bull. Nat. Moscou. no, 

 \. pis, 1-2. 1899. 



3. Belajeff, W., Zur Lehre von den Pollenschlauche der Gymno- 

 spermen, Ber. Deutsch. Bot. Gesell, 11 : 196-201.^/. 12. 1893. 



4. Chamberlain, C. J., Oogenesis in Pm^is Laricio. Box. Gaz. 27 :268- 

 2?»o. pis, 4-6, 1898. 



5. CoKER, W. C, Notes on the gametophytes and embryo of Podocarpus. 

 BoT. Gaz. 33 : 89-107. //y.j-7. 1902. 



6. Coulter, J. M., Notes on the fertilization and embryogeny of 

 conifers. Box. Gaz. 23 : 40-43.//^. 6. 1897. 



7. Coulter, J. M. and Chamberlain, C. J., Morphology of sperma- 

 tophytes. Part I. New York. 1901. 



8. Ferguson, Miss M. C, The development of the pollen tube and the 

 division of the generative nucleus in certain species of pines. Annals of 

 Botany 15 : 193-223. /Zy. 12-14., 1901. 



9. Jager, L., Beitrage zur Kenntniss der Endospermenbildung und zur 

 Embryologie von Taxus baccata. Flora 86 : 241-288.//^. 15-ig^ 1899, 



10. LOTSY, J. P., Contributions to the life history of the genus Gnetum, 

 Ann.Jard. Bot. Buitenzorg II. i : 46-11 4.//^. 2-1 1, 1899. 



11. Strasburger, E., Die Angiospermen und die Gymnospermen. 1879. 



EXPLANATION OF PLATES VI-VIIL 



The figures, with the exception of figs. 8, 9, 10, 11, and 2B, were drawn 

 with Abb6 camera lucida, Bausch and Lomb ~^^ objective and ocular 2, For 

 figs* S, g, 10, II, and 28 a Bausch and Lomb \ objective and ocular 2 were 

 used. The magnification oifigs, 8, g, 10, 11, and 28 was 450; all others 850. 

 The plates are reduced to one-half the original size. The abbreviations 

 used are : b^ body cell ; v, ventral nucleus ; m, male cell ; o^ egg nucleus ; 

 s, suspensor 



