64 



INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



There seems to be no doubt that the endothelium is a nutritive 

 layer whose chief function is to serve as an intermediary for the 

 transport of food materials from the integument to the embryo sac. 



E F G H I 



Fig. 45. Diagram illustrating derivation of the female flower and ovule of Bala- 

 nophora. A, l.s. hypothetical ovary showing two ovules. B, ovary of Thesium. 

 C, ovary, as in Osyris, Santalum and Myzodendron. D, as in Arceuthobium and 

 Helosis. E, as in Korthalsella. F, as in Viscum and Dendrophthoe. G,H, as in 

 Scurrula. I, as in Balanophora. {After Fagerlind, 1945d.) 



Some writers also claim that it contains diastase and other enzymes 

 which convert the food into a suitable form for the use of the embryo 

 sac. In later stages, when the embryo is approaching maturity, 



