THE AXGIOSPERAIAE 



1455 



or, on the other hand, the single nucleus included may divide and produce 

 a multinucleate cell. In either case the nuclei later fuse, so that rarely is 

 more than one left in each cell. 



■. *'l*-j*rK»!«:V»:3'"-*^WJ^ f'^ 



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Fig. 1334. — HeluuithemiDn ctiamaecistus. Cell formation in 

 the endosperm. Se\eral cells contain more than one 

 nucleus. 



Wall formation in nuclear endosperm may sometimes be suppressed and 

 the nuclei remain free but the examples are not numerous and are scattered 

 in different families as a specific peculiarity. Among well-known instances 

 are: Acer pseudoplataniis, Aescidus hippocastaninn, Myricaria germanica and 

 Limnanthes doiiglasii. Further, it occurs in many Melastomaceae and in the 

 tribe Viceae of Papilionaceae. All these are plants in which the development 

 of the endosperm is incomplete and soon ceases, the ripe seeds being non- 

 endospermic. 



Peripheral endosperm formation does not always fill the whole sac and a 

 central space containing fluid may be left, the most striking example being 

 that of the Coconut, where the space is relatively enormous. 



In the cellular type of endosperm formation there is no free-nuclear 

 O 



