ON VEGKTABLE PHYSIOLOGY. 73 



more perfect parts within. It is consequently 

 made of stronger materials, that it may thus per- 

 form its functions uninterruptedly. 



The corolla or blossom, in which all the beauty 

 of the flower is invested, is supposed to be an ex- 

 tension of the inner or vascular part of the bark ; 

 and consists either of a single piece, or most fre- 

 quently of many pieces that have been denomin- 

 ated petal or petals ; and these are found to 

 contain an infinite variety of small tubes of the 

 porous kind, intended (as it is conjectured) for 

 the absorption from the atmosphere and from 

 the rays of light, of those renovating materials 

 which are to contribute to the support and fertility 

 of the more essential parts of the flower ; while 

 the corolla generally, defends and protects those 

 parts from external injury. The mechanism of 

 iqe petals therefore is of a very delicate and mi- 

 nute character ; and the corolla, by encircling the 

 internal parts with its foliage, is well calculated 

 to answer the defensive purposes to which we 

 have alluded. 



The receptacle is the base of the flower close 

 to the stalk upon which all the other parts rest, 

 as may be seen in the artichoke, when the leaves 

 are removed ; and which, no doubt, though we 

 may not comprehend it, serves some other useful 

 purpose in the economy of vegetation, indepen- 

 dently of the support it affords to the flower. 



The nectarium, or nectary, consists of a small 



