408 BOTANICAL GAZETTE [may 



first division of the oosphere nucleus is parallel or oblique to the long 

 axis of the ovule and is approximately in the center of the original 

 nucleus. The 



norm 



to the long axis of the ovule and lies quite at the top of the original 



oosphere nucleus. In both cases this spindle is entirely intranuclear, 



as shown by Chamberlain, 2 and some of the original achromatic nuclear 



material is not used up, but contracts considerably from the original 



nuclear membrane. (This contraction may be due to the action of fixing 



or other reagents, but as it is equally present in all preparations, whether 



or not any contraction has occurred elsewhere, I am inclined to think it 

 normal.) 



4. In normal fertilization a segregation of the chromosomes into two 

 groups occurs both in the first and second divisions of the oospore nucleus, 

 but no segregation can be seen here (fig. 3). The chromosomes are long 

 and rather irregular in shape and are often cut into several pieces and 

 distributed through as many sections. It has therefore been impossible 



normal 



oiftg 



*w/ WW X 



certainly less than that number. 



5. In normal fertilization a good deal of disorganization of the apical 

 part of the archegonium occurs, and the receptive vacuole is either broken 



(fig 



H 



1 and 2 were drawn, no such disorganization has occurred, and the receptive 

 vacuole occupies its normal position. 



6. In normal fertilization the remains of the second sperm nucleus and 

 the tube nucleus and the stalk cell can be distinguished for a time in the 

 upper part of the archegonium, but no trace of these nuclei can be found 

 in the archegonia of Jigs, i and 2. 



As far as has been seen, the abortion of the ovule frequently occurs 

 before the formation of a proembryo, but never after. A large number of 

 preparations of the proembryos and embryo in all stages of development 

 leaves no doubt on this point. Hence it appears that parthenogenetic em- 

 bryos must develop as well as normal ones. It is impossible to say whether 

 this development is only intiaseminal, or whether seeds containing such 

 embryos are able to germinate and produce normal plants. 



Fig. 5 shows, for the sake of comparison, a case of normal fertilization, 

 and the conjugating nuclei are shown in more detail in Jigs. 6 and 7. The 

 preparation shows very clearly that the nuclear membranes are not in 



' Chamberlain, C. J., Methods in plant histology. Second edition. The U 

 versity of Chicago Press. 1905. 



