88 



MORPHOLOGY OF AXGIOSPERMS 



is in brief outline a history whose beginnings are entirely con- 

 jectural. Its uniformity throughout so vast a group of plants 

 testifies to its long establishment. The evanescent cell-plate 

 frequently observed during the three free nuclear divisions by 





Fig. 37. — A. Liliuni pTiiladelphicum, second nuclear division in the embryo-sac: the 

 persistence of the spindle from the first division indicates that the second division 

 has followed very rapidly; x 450; after Schaffner. 48 B, L. philadelphicvm, 

 third nuclear division: two of the spindles show the beginning of a cell-plate; 

 x 450; after Coulter. 46 C, Ranunculus multifidus, fusion of polar nuclei to form 

 endosperm nucleus; x 600; after Coulter «; «, synergids; o, oosphere, fusing 

 polar nuclei in central region: a, antipodals. 



which the eight-nucleate stage of the embryo-sac is reached, the 

 frequent organization of cells about the three antipodal nuclei, 

 the frequent division of the antipodal cells resulting in a more 

 or less extensive tissue, and the additional nuclear divisions ob- 

 served in Peperomia and other forms, are evidences that the 

 present female gametophyte of Angiosperms is a much reduced 

 descendant from multicellular ancestral forms, with forms like 

 Gnetum as the nearest approach to the present conditions; but 

 there seem to lie no nearer records of its connection with the 

 histories of other female gametophytes. The female gameto- 

 phyte of Angiosperms, therefore, is a morphological problem of 



