BOOK II. 



ANATOMY OF PLANTS. 



CHAPTER I. 



THE VEGETABLE CELL. 



If we study the life -history of the simplest or the most complex 

 plant with which we can become acquainted, we find that at 

 some time or other in its existence it is found in the form of a 

 minute portion of jelly-like substance, in some oases motile, in 

 others incapable of locomotion. The gametes which are developed 

 upon the filamentous 



Seaweedsaresuehlittle I'lO- *J09- 



naked masses. In the 

 lowest plants, such as 

 Ulotlirix {fig. 609), 

 these are ovoid bodies, 

 furnished with long 

 narrow appendages, by 

 means of which they 

 swim actively about in 

 water. The zoospores 

 and zoogonidia of many 

 other Algae are similar 

 in structure. The jelly- 

 like substance of which 

 they are composed is capable of carrying on all the processes of 

 their life, and is, in fact, the livin,(/ substance ; it is called jjroto- 

 plasm. Many of the small reproductive bodies already described 

 differ from these free-swimming organisms in having the proto- 

 plasm clothed by a thin almost structureless membrane which 



y-V;/. 609. Part of a filament of Ulolhrix from 

 which the gametes, g, are escaping. g\ Free 

 gamete, g-, (f. Gametes conjugating. 



