422 BOTANICAL GAZETTE [December 



definitive archesporial cell. The latter divides into three (usually 

 four) potential megaspores. The lower or chalazal one of these 

 is the functional one, the remaining three degenerate and are 

 absorbed. The mature 7 -nucleate embryo sac is of the type most 

 characteristic of angiosperms. 



6. The endosperm nucleus, embodying two polar nuclei and 

 possibly a male nucleus, begins to divide before the oospore. Its 

 first division is immediately followed by a transverse wall which 

 divides the embryo sac into upper and lower cells. Each of these 

 two cells continues to divide repeatedly, thus forming the thousands 

 of endosperm cells that completely fill the mature seed except for 

 the embryo. The several layers immediately surrounding the 

 embryo are at this time devoid of starch. 



7. The fertilized egg begins to divide only after 15-20 endosperm 

 cells have been formed. The synergids and antipodals degenerate 

 by the time of the first division of the oospore. 



8. The ripe seed consists of a globular mass of cells with a poorly 

 developed suspensor. The seed coat is not developed appreciably. 

 Its function is obviously performed by the wall of the ovary. 



9. At germination the small embryo is for a long time inclosed 

 and nourished by the swelling endosperm. The cotyledons 

 remain in the endosperm until nearly all its starch is exhausted. 

 They are then withdrawn and assume an active photosynthetic 

 function. 



Johns Hopkins University 



Baltimore, Md. 



LITERATURE CITED 



1. Baillon, H. E., Nat. Hist. Plants 3:1874. 



G., and Hooker, J. D., Genera 



Ann. Botany 



3. Campbell, D. H 



pellncida Kunth. Ber. Deutsch Bot. Gesells. 17:1899. 



4- , A peculiar embryo sac in Peperomia pelluc 



13:1899. 



5. Clarke, B., The structure and affinities of the Myricaceae and Chloran- 

 thaceae. Ann. and Mag. Nat. Hist. III. 1:1858. 



6. Eichler, A. W., Bluthendiagramme 2:1878. 



7. Exgler, A., and Prantl, K., Die Natiirlichen Pflanzenfamilien III. 

 1:1893. 



