ANATOMY AND PHYSIOLOGY OF PLANTS. 237 

 OF THE CALYX. 



2. The calyx is said to be constructed, like the leaves, 

 of a cuticle, a pretty thick cellular tissue, and of vessels r 

 all of which exist in the foot-stalk, and are derived 

 from the common textures of the plant. 



This organ of the flower assumes a variety of forms. It is some- 

 times asingle leaf, and has a tubular form ; in others, of many leaves, 

 giving it a great change in appearances. Its colour is usually green 

 but sometimes coloured. 



3. The purport of the calyx, is unquestionably, to 

 protect or assist the economy of fructification. 



Its principal use is said to be, to protect the infant flower, which 

 observation contributes to confirm. In some instances, the calyx 

 falls when the flower has expanded or the fruit has set ; in others, 

 it continues till the seed is mature ; while in a few instances, the 

 fruit or seed is formed within it, to which it becomes a permanent 

 receptacle or covering, and performs the oflice of a seed-vessel. 



OF THE COROLLA. 



4. With regard to the structure of the corolla, it is 

 described as composed of the same textures as the com- 

 mon leaf, as is distinctly seen in the thicker varieties 

 of it. 



Grew showed it to possess spiral vessels, a proof, as Du Hamel 

 observes, that it is partly derived from the woody textures of the 

 plant, since such vessels are not found in the bark. 



5. The undoubted object of the corolla, is to defend 

 the interior organs of the flower from the changes of the 

 atmosphere, and to assist either directly or indirectly, 



