APOMIXIS 



333 



Fig. 191. Semigamy in Rudbeckia speciosa. A, part of embryo sac, showing two- 

 celled endosperm and egg containing male and female nuclei. B, egg, showing 

 division of both male and female nuclei. C,D, two-celled proembryos; two small 

 nuclei in basal cell have arisen b.y division of sperm nucleus. E, three-celled pro- 

 embryo showing nuclei derived from sperm in terminal cell. F-H, more advanced 

 stages; nuclei derived from sperm occupy variable positions in proembryo. (After 

 Batiaglia, 1947.) 



