FERTILIZATION 



207 



sometimes the fertilization of an antipodal cell may also occur in 

 Ulmus. 



Embryo sacs which have received more than two sperms may also 

 show other abnormalities. Frisendahl (1912) noted that in Myri- 

 caria germanica each of the polar nuclei may sometimes fuse with a 



Fig. 117. Some abnormalities of fertilization in Crepis capillaris. A, upper part 

 of embryo sac, showing four eggs and two sjmergids. B, four egg-like cells and 

 two-celled embryo. C, supernumerary sperm near apex of embryo sac; two eggs, 

 one in prophase and the other in metaphase, and two dividing endosperm nuclei. 

 D, portion of pollen tube, showing two pairs of sperms and unidentified body at 

 upper end which may be one of a third pair of sperms. (After Gerassimova, 1933.) 



separate male nucleus. 7 In Acacia bailcijana, Newman (1934) ob- 

 served division figures of the primary endosperm nucleus showing 

 4:n, 7n, and 8n chromosomes. 8 Since such embryo sacs seemed to 

 have received more than one pollen tube, it is inferred that extra 



7 Since the upper polar nucleus in Myricaria is haploid and the lower triploid, 

 some of the endosperm nuclei would be diploid (n + n) and some tetraploid 

 (3 n + n). 



8 Rarely he found only the haploid number of chromosomes, presumably due to 

 an independent division of either a polar nucleus or a male nucleus. 



