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 18 ) 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 

 greatly (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 



B 



FIG. 79. Sagittaria variabilis. A, two nuclei of endosperm separated by wall : a, an- 

 tipodals, x 200 ; B, compact endosperm tissue developed from upper cell, the lower 

 merely growing large without dividing; x 108. After SCHAFFNEK. IB 



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- 



