342 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



cell can be seen. Almost the last stages in the existence of 

 the antipodals is shown in figure 28. The protoplasm of the 

 antipodal cells is the first portion of the cells to disappear; 

 traces of the antipodal nuclei are frequently met when they 

 are quite disassociated from the protoplasm of the cells. The 

 function of the great antipodal complex, in those forms in 

 which it is present, undoubtedly varies with the time of its 

 formation. In the oat, as in the wheat (Koernicke), the 

 antipodals are formed prior to fertilization and disappear 

 with the multiplication of the endosperm nuclei, being con- 

 sumed by the endosperm in its development. In Spci?'- 

 ganiiim (Campbell) the antipodals multiply enormously 

 after fertilization, and evidently function as endosperm, and 

 consequently serve to nourish the growing embryo. 



V. Fertilization and the Building of the 

 Endosperm. 



The pollen-tube enters the embryo-sac by pressing apart 

 the cells of the micropyle. The two synergidae do not 

 usually disappear at this time, although one seems to do so. 

 This point needs further study. One, or perhaps the two 

 synergidae, may sometimes be observed partly resorbed 

 while the embryo is still in the proembryo stage, and it is 

 likely here, as in the wheat (Koernicke), that both syner- 

 gidae are consumed as nourishment for the young embryo. 

 The phenomena associated with the union of the sexual 

 nuclei, as well as the further history of the pollen-tube, 

 the vegetative nucleus, and second generative nucleus were 

 not followed. 



The endosperm nucleus begins to divide about the time 

 when the ^gg is fertilized ; but whether this precedes or 

 follows the union of the nuclei was not determined. At the 

 first division of the &gg a few endosperm nuclei may be 

 seen in the thin protoplasmic lining in different parts of the 

 embr3'0-sac. These nuclei vary a great deal in size, and in 

 shape also, from spindle form to a flattened sphere. Each 

 endosperm nucleus generally contains several (three to 

 eight) nucleoli. In the early stages in endosperm formation 



