THE ENDOSPERM 



175 



relative size of the chambers depends upon the position of the 

 dividing nucleus (Fig. 74). 



Among Monocotyledons, the endosperm of Sagittaria 

 (Schaffner 1S ) develops rapidly in the micropylar chamber 

 into a -walled tissue, the endosperm nucleus of the antipodal 

 chamber enlarging much but not dividing for a long time, when 

 two or three nuclei may be formed, all of them increasing 

 greatlv (Fig. 79). Practically the same thing occurs in Limno- 

 charis (Hall 50 ), but the nucleus of the antipodal chamber en- 

 larges without dividing. In Ruppia rostellata (Murbeck 58 ) a 



Fig. 1$.— Sagittaria variabilis. A, two nuclei of endosperm separated by wall : a, an- 

 tipodal, x 200 ; £. compact endosperm tissue developed from upper cell, the lower 

 merely growing large without dividing; x 108.— After Schaffner. 18 



wall is formed at the first division of the endosperm nucleus, the 

 antipodal chamber remaining small and with undividing nucleus, 

 but a large number of free nuclei being formed in the micro- 



