THE EMBRYO 



295 



pensor cells soon lose their connection with the main body of this 

 organ and occur merely as islands within the endosperm. Further, 

 sometimes they degenerate even before the connection is lost, and if 

 this be so, they naturally cannot function effectively as absorbing 

 organs. 



B 



Fig. 167. Suspensor haustoria of Asperula. A, young embryo with prominent 

 suspensor haustoria; the surrounding cells belong to endosperm. B, older stage, 

 showing extreme development of haustoria. (After Lloyd, 1902.) 



The suspensor haustoria of the Halorrhagidaceae bear a remarkable 

 resemblance to synergids (Fig. 168 A-G). Stolt (1928) and Soueges 

 (1940) have shown that in Myriophyllum the two-celled proembryo 

 consists of a large basal cell and a much smaller terminal cell. The 

 former divides longitudinally to form two daughter cells, which 

 enlarge to such an extent as to occupy the entire space in the micro- 

 pylar part of the embryo sac. They remain distinguishable even 

 up to the time of differentiation of the cotyledons. 



Three members of the family Fumariaceae are also of much 

 interest in this connection. In Hypecoum (Soueges, 1943a, b) the 



