FERTILIZATION IN PLANTS 



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egg (Fig. 108); and the earlier observers of the angiosperms, includ- 

 ing Strasburger ('84, '88) and Guignard ('91, i), likewise found that 

 only one of the generative nuclei entered the embryo-sac. Guignard 



Fig. 107. Fertilization in the lily. [D from MOTTIER, the others from GUIGNARD.] 

 A. Embryo-sac, ready for fertilization. B. Both generative nuclei have entered the embryo- 

 sac ; one is approaching the egg-nucleus, the other uniting with the upper polar nucleus. C. Union of 

 the germ-nuclei ; below, union of the second generative nucleus and the two polar nuclei. D. The 

 fertilized egg, showing fusion of the germ-nuclei. E. The fertilized egg dividing; below, division 

 of the endosperm-nuclei, a. antipodal cells ; e. endosperm-nuclei; o. the oosphere or ovum; 

 /. polar nuclei ; p. t. pollen-tube. 



and Nawaschin have, however, recently made the remarkable dis- 

 covery that in Lilium and Fritillaria both generative nuclei enter 

 the embryo-sac. One of these conjugates with the egg-nucleus and 



