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formation. In certain ovules I found stages which I have brought 

 together in fig. IX and which probably may be explained in the 

 following manner. There has been a typical reduction division, 

 but after the second division no cell wall has been formed between 

 the daughter nuclei (A). These come nearer together (B) and 

 finally unite (C). Especially the behaviour of the nucleolus (D) 

 supports this supposition. Such figures, however, are so rare, that 

 this form of ES-formation cannot be considerad to be of great 

 importance for embryo formation in this species. I hope to be 



A B 

 Fig. X. Polyembryony in H. excellens. 



able to explain this more definitely with more abundant and sui- 

 table fixed material. Perhaps we have here a case similar to that 

 in parthenogenetic eggs in certain insects, where the third polar 

 body remains in the egg and becomes united with the egg nucleus. 



I have also investigated a form of H. Pilosella which is always 

 sterile in Copenhagen (Ostenfeld 16, p. 246). A cytologicai 

 investigation upon the ES-formation showed that a typical reduc- 

 tion division proceeds, and that the lower cell of the tetrad be- 

 comes the embryo sac in the ordinary way. In this species I have 

 never seen aposporic ES-formation. The embryo sac becomes 



