A CD 



Fig. 177. Origin of haploid embryos in Solatium nigrum after pollination with 

 S. luteum. A, mature embryo sac of S. nigrum, showing egg, secondary nucleus, 

 one synergid, and the antipodals. Note sperm nucleus inside egg. B, egg with 

 two sperm nuclei. C, upper part of embryo sac, showing disintegrating sperm 

 nucleus inside egg. D, young embryo and part of endosperm. (After J^rgensen, 

 1928.) 



Fig. 178. Development of synergid embryos in Lilium martagon. A, apical 

 portion of ovule, showing first division of zygote and synergid. B, two-celled 

 zygotic proembryo; division of synergid not yet completed. C, twin proembryos; 

 smaller proembryo, on left, has arisen from a synergid. D, more advanced stage; 

 proembryo on right has arisen from an unfertilized synergid and is haploid ; proem- 

 bryo on left has arisen from fertilized egg and is diploid. (After Cooper, 1943.) 



315 



