230 INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



oblique, and in Senecio (Afzelius, 1924) there is no constancy about 

 its orientation. Frequently it is longitudinal, but it may also be 

 transverse or oblique. 



A B C 



Fig. 125. Formation of lateral haustorium or diverticulum in embryo sac of 

 Agrostemma githago. A, l.s. ovule, showing early stage in formation of diverticulum. 

 B, enlarged view of embryo sac from A. C, l.s. nearly mature seed, showing large 

 embryo and persisting diverticulum. (After Roccn, 1927.) 



C D 



Fig. 126. Early stages in development of endosperm in Adoxa moschatellina 

 (A-C) and Centranthus mncrosipJwn (D). In both cases, the first wall is vertical. 

 (A-C, after Lagerberg, 1900; D, after Asplund, 1920.) 



Except in the few plants cited above, the first division of the endo- 

 sperm mother cell is generally transverse. In the Anonaceae, 

 Aristolochiaceae, Sarraceniaceae, Gentianaceae, Boraginaceae (see 



