56 COMPOUND ORGANS OP PLANTS. 



In them we see organization brought, by successive degrees of 

 simplification, to the utmost degree of structural simplicity. 

 We have seen that all the different forms of tissue found- in 

 plants are only modifications of the cellular, all originating in 

 the simple cell as a point of departure ; and in like manner, 

 when we look on the plants themselves individually, and fol- 

 low the operations of nature in detail, as seen in the lower 

 vegetation, it may be truly said that the same simple cell is 

 the starting-point of the plants themselves, considered as indi- 

 viduals. 



63. It is not necessary for cell-development to be carried to 

 any great extent in order to constitute the fabric of a true and 

 perfect plant. All the organs which constitute the most com- 

 plete vegetable concur in the exercise of one or the other of 

 two general functions, nutrition and reproduction, and we have 

 seen that these functions may be exercised by plants composed 

 of a single row of cells strung end to end, or may be confined 

 to one and the same cell, as in the Protococcus and the various 

 species of leprarias or pulverulent lichens (51), which are 

 plants composed of a mass of free spherical utricles, or cells 

 filled with granulations of various colors. 



64. It is at this point that the Vegetable makes the nearest 

 approach to the Animal kingdom, which also has for its start- 

 ing-point a single spherical utricle or cell, which differs only 

 from the vegetable cell in that it possesses the property of 

 motion. The two series, the animal and vegetable, there- 

 fore, commence in the same manner, and hence it is not in 

 plants which are the most perfect, but, on the contrary, in 



