THE ENDOSPERM 



173 



appear many nuclei are always enclosed in each cell and sub- 

 sequently fuse. In this particular case the free nuclear divi- , 

 sions are often irregular, and of course the number of chromo- 

 somes is exceedingly variable, a fact very common in all endo- 



FIG. 7S. Advanced stages in development of endosperm. A, Reseda, odorata, upper 

 part of figure showing free nuclear division, while in lower part nuclear division is 

 accompanied by formation of cell walls ; x 860 ; B, Caltha palustris, showing all 

 nuclear divisions accompanied by formation of walls, x 155; (7, CorydaUs cava. 

 showing free nuclear division within cells of endosperm; D, the same, showing 

 multinucleate endosperm ; x 860. After STRASBURGZR.* 



sperm. The same phenomenon was observed by Humphrey 17 

 in Canna indica, in which the parietal layer of free nuclei 

 becomes blocked out by walls, each " block " containing several 



