242 INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



Celsia, and Ilysanihes, or fuse to form a common tetranucleate 

 structure as in Vandellia and Torenia. In a few plants like Pedi- 

 cularis the haustorium is tetranucleate from the commenceirent. 



A B C 



Fig. 135. Development of endosperm in Lathraea squamaria. A, first division of 

 endosperm mother cell. B, nuclear division in both endosperm cells. C, division 

 completed; basal cell binucleate and upper cell partitioned by longitudinal wall. 

 D, basal cell forms large haustorium; transverse division in upper cells to form 

 two-celled micropylar haustorium and two central cells, which are destined to give 

 rise to main body of endosperm. (After Glisic, 1932.) 



In Centranthera neither the micropylar nor the chalazal haustorium 

 is very active, but there are formed instead some secondary haustoria 

 from the endosperm cells just beneath the micropylar haustorium 

 (Fig. 137). Similar secondary haustoria are seen in Veronica, but 

 here they arise from the chalazal region of the haustorium. 



