CONIFERALES 341 



Double fertilization, as it occurs in angiosperms, may not occur in 

 gymnosperms; but it is worth noting that Land^-'^ found fertilization 

 of both the egg and ventral canal cell nucleus in Thuja; and Hutch- 

 iNSON^^s found the same thing in Abies. In both, there were two 

 similar groups of cells, one at the top and the other — the young 

 embryo — at the bottom. 



The term "fertilization" is not easy to define. Practically, when 

 teachers order slides showing fertiHzation from biological supply 

 companies, they accept anything showing the sperm within the egg. 



