10 



fused in auch a manner, that thu (jrigin from two nuclei. 

 can still be seen (flg. 10). 



The fertilized ovum now rapidly enlarges, whilo ail other 

 cells in its neighbourhood are crowded ont (fig. 10). As 

 the epidermal cells of the nucellns hâve generally aborted, 

 this large cell lies more or less by itself in the endosto- 

 mium, almost fllling it up. By the first division wall there 

 is formed a bladder-like basai cell, which remains in the 

 cavity, and a smaller one, which is gradually pushed for- 

 ward mto the pseudo-embryosac. This cell now undergoes 

 some divisions, in which the walls are formed perpendi- 

 cular to the long axis of the young seed (flg. 11). When 

 a row of four cells has thus arisen, the three wich are 

 turned towards the micropyle become a suspensor, while 

 the fourth divides by a wall at right angles to the pre- 

 vious ones and becomes the embryo proper. 



1 hâve not traced the further development of the embryo, 

 partly for wantof sufficient material, but especially because 

 Warming has already furnished an excellent treatise dea- 

 ling with this subject, and illustrated \w\t\i figures. Considering 

 the many new facts, which Willis has discovered about 

 the germination of the Podostemaceae of Ceylon, an investi- 

 gation of the American forms in this direction would 

 certainly repay, since through G o e b e 1 we hâve only learned 

 in détail of a single case. For this an investigation on 

 the spot is necessary, and as will appear from the full 

 paper, I hâve not been able to find much that is new in 

 this direction. 



What was hitherto known about the ovules of Podo- 

 stemaceae we owe almost exclusively to W a r m i n g. As was 

 said above, this author described in détail the first deve- 

 lopment of the ovules of Mniopsis Weddelliana Tul, and 

 it was only owing to the want of the exact stages, that 

 the meaning of certain oi'gans did not become clear to 



