FIG. 99. Median longitudinal sections of younK ovule*, a. Showing primary archc- 

 sporial cell ( 260) ; b, after its first division ; r, tetrad M.IKC ; </. inner cell of 

 tetrad after the collapse of the three outer cells. Outlines of the two ovular integu- 

 ments arc shown (b, c, d 350). 





Fie;. 100. Kni! apparatus and fusion- 

 nuclei (June 12) ( 350). 



l-|i;. 101. Knihryo-sac before fertilisation 

 (June i .:) ( ^So). 



