100 



MORPHOLOGY OF ANGIOSPERMS 



before and after fertilization and becoming multinucleate; 



those of various species of Ranunculus, Anemonella, and Thal- 



ictrum dioicum as very large: and 

 those of Hepatica as growing very 

 much until after fertilization. Since 

 then Overton n0 has found that the 

 antipodals of Thalictrum purpuras- 

 cens become remarkably large, reach- 

 ing the center of the sac ; Misa 

 Dunn 8y has reported that in Del- 

 phinium exaltatum three very large 

 antipodals persist even in the oldest 

 seeds with no indication of degen- 

 eration; Miss Lyon has noted as 

 many as twenty-live antipodal cells 

 in Hepatica ; and Osterwalder 60 has 

 figured exceedingly large antipodals 

 in Aeon it inn Xa pell us (Fig. 46). 

 The whole family is characterized, 

 therefore, bv the activity of its an- 

 tipodal cells, exhibited more by their 

 great increase in size than by divi- 

 sion. Among the Amentiferae Miss 

 Benson 31 reports a row of six or 

 more superposed antipodals in the 

 very narrow antipodal end of the 

 sac in Castanea vulgaris, the lowest 

 one being figured as the largest and 

 multinucleate, the whole structure 

 resembling the antipodal region of 

 many Compositae. Around the base 

 of this elongated antipodal region 

 there are developed such tracheid- 

 like cells as occur in the micellus 



Fig. 47. — Aster novae-angliae. Longitudinal sec- 

 tion of embryo-sac just before fertilization: 

 m, micropyle: .«. synersrid ; o, oosphere; e, en- 

 dosperm nucleus : t, jacket: A, lower antipodal 

 cell: tour other antipodal cells shown, the 

 upper with four nuclei and the others with two; 

 x 407. — After Chamberlain. 35 



