66 



PLANT LIFE. 



(see fig. 76). In many of the seed -plants the egg divides 



several times in parallel planes, forming a 

 short filament, the suspensor (figs. 7982). 

 The terminal cell of this row may then 

 give rise to an embryo, as just described, 

 or this terminal cell and an adjacent one 

 may take part in forming the embryo. In 

 this case the terminal cell, bv its divisions, 



' - 



either produces the primary leaf or leaves, 

 Fl emb 7 ry7VthI IS. or it: Produces the primary stem and 

 sor- J n V h cefis S from l eaves \ while the second cell gives rise to 

 ve^fs^liirHaEt the Primary stem and root, or to the 

 fied. -After Sachs. primary root alone (see figs. 80-82). 

 The two primary members formed 

 from the root hemisphere of fernworts 

 are not always permanent. The foot is 



FIG. 80. FIG. 81. 



FIG. 80. A very young embryo of shepherd's-purse. Suspensor, j, j. just completed, 

 and first four cells of embryo formed by division of terminal one ; the second cell, 

 l>, is to produce part of the root. Highly magnified. After Hanstein 



FIG. 81. An older stage of the same. E, embryo; b 1 ', 6", two cells resulting from 

 division of b. fig. 80 ; j, .?. suspensor. The shaded cells produce the skin and the 

 vascular bundles Highly magnified. After Hanstein. 



FIG. 82. An older embryo of same. , embryo; /, /, primary leaves: sf. apex of 

 stem ; r, primary root ; re, first layer of root-cap; s, suspensor. Cells shown only 

 in part. Less magnified than preceding. After Hanstein. 



