324 BOTANICAL GAZETTE [November 



sistent synergids have well-marked cell walls {fig^ lo). The 

 large endosperm nucleus is found in a considerable mass of pro- 

 toplasm, usually near the middle of the embryo sac {^fig- lo^ espn). 

 The distinct antipodals early become sunken in the very bottom 

 of the embryo sac. They seem never to increase in number nor 

 greatly in size, but persist, though slightly crushed, even in the 

 ripe seed {figs. 12, /j, 14). During the ripening of the embryo 

 sac it continues to broaden, and when the endosperm begins to 

 form it is nearly globular {fig. ij), and in the ripe seed it may 

 be even broader than long {fig. 14) . 



No clear evidence of fertilization or even of the penetration 

 of the pollen tube to the embryo sac has been obtained. Many 

 pollen grains were found on the stigma, some of which had evi- 

 dently begun to germinate. 



In the further development of the embryo sac the endosperm 

 nucleus is at first most active. This nucleus divides repeatedly 

 by mitosis. The daughter nuclei become distributed throughout 

 the peripheral cytoplasmic layer of the embryo sac {fig^ -^^)» 

 and after twenty or more free nuclei have been formed cell-walls 

 appear between and about these, and a peripheral layer of cellu- 

 lar endosperm is formed {fig. ij). Later the central vacuole is 

 filled up with endosperm cells {fig. 14), probably by the division 

 of those of the peripheral layer, since no free nuclei were dis- 

 covered in the vacuole within the first layer of endosperm cells 

 formed. In the ripe seed the endosperm forms a somewhat top- 

 shaped mass of several hundreds of cells {fig- 14)- 



During this development of the endosperm the ^gg changes 

 but little except in size at first {figs, 10, 12, ij), but later it 

 divides up to form a globular embryo, which in the oldest seeds 



(probably ripe ones) consisted in longitudinal section of 

 thirty or forty cells, and showed no differentiation save a slightly 



seen 



(/^. 



iM 



12, ij), though the former were not seen in the ripe seed. 



In the mature seed the embryo is about 0,06'^°' in diameter, 

 the endosperm is 0.3"*°^, and the whole seed from micropyle to 

 basal wall 17™^ long by 1.2"*"' broad in the middle. 



