PRINCIPLES OF BOTANY. 



DIVISION I. 



ANATOMY. 



CHAPTER I. 



Organized Vegetable Elements. 



1 . The organized vegetable elements are those primi- 

 tive formations to which we can reduce the most com- 

 pound structures of plants, but beyond which we can 

 analyse no further ; and these primitive formations are 

 the results of, and obey and perform the laws of vital 

 action. 



2. These elements are two in number, Membrane and 

 Fibre. 



3. Membrane has in general the appearance of a 

 tender, uniform, and diaphanous layer, separating from 

 itself with an even edge, and is devoid of colour ; 

 when moist, appearing slightly stretched, but when 

 dry, coming together and exhibiting wrinkles. Mem- 

 brane may be found coloured, however, especially in 

 many of the lower tribes of plants, as well as in the 

 cuticle of some of the higher orders. The action of the 

 mineral acids upon membrane is in general destructive, 

 except, according to Meyen, upon the membrane form- 

 ing part of the structure of the grains of pollen. 



B 



