92 



ILLINOIS STATE ACADEMY OF SCIENCE 



FORMATION OF THE COTYLEDONS 



The proembryo is spherical. I find no snspensor. My 

 preparations seem to conform to those of Lyon (6) and 

 York (7). However, in the light of later ideas of plant 

 phylogeny I should place new interpretations upon them. 

 The spherical embryo at first slightly elongates in the 

 line of the long diameter of the embryo sac, (Figs. 2, 3). 

 Soon it widens at right angles to the preceding elonga- 

 tion (Fig. 4), showing two actively growing points on 



Figs. 7 and 8. 



opposite sides of the periphery and a meristematic tip 

 in the center. One of the peripheral growing points is 

 much more active than the other, producing a single coty- 

 ledon (Fig. 5). Shortly after this the second growing 

 point increases its activity and a second cotyledon ap- 

 pears (Fig. 6). The region between the two cotyledons 

 grows very slowly. So rapid is the growth of the second 



