THE EMBRYO 



285 



(Fig. 159E). The cell cd, sister to cc, divides into two superposed 

 cells m and ci (Fig. 159C) of which the former again segments into 

 d and / (Fig. 159D). Subsequently I and V produce the cotyle- 

 donary and hypocotyledonary parts of the embryo; d becomes 

 differentiated as the hypophysis; and the cells /, ci, and cb con- 

 tribute to the formation of a filamentous suspensor. Occasionally 

 a few vertical divisions may also take place in the suspensor, but 

 these are sporadic and of no importance. 



B 



D 



Fig. 159. Development of embryo in Androsaemum officinale. 

 Soueges, 198Gb.) 



E 



(Redrawn after 



The embryogeny of Drosera rotundifolia (Soueges, 1936c) is pe- 

 culiar in that it shows points of resemblance with three or four 

 different types of embryonal development. The basal cell cb under- 

 goes only one or two divisions to give rise to a short suspensor. The 

 terminal cell ca divides transversely into two superposed cells cc 

 and cd (Fig. 160A-C). The former again divides transversely to 

 form two cells I and V (Fig. 160Z)) both of which become vertically 

 partitioned to form first quadrants (Fig. 1Q0E) and then octants 

 (Fig. 160F). Meanwhile, cd also undergoes a transverse division 

 into two superposed cells h and h', both of which become partitioned 

 by vertical walls (Fig. 160E,F). Regarding the further fate of these 



