OF DEPOSITS OF NOURISHMENT. 275 



that they result from the union of several neighbouring 

 branches upon the same plane. 



Fasciculated stems must not be confounded with 

 stems or branches which have the cortical parenchyma 

 so extended upon their two opposite sides as to give 

 them the expanded appearance of a foliaceous limb ; 

 thus, several species of Cactus, as C. Pkyllanthus and 

 Opuntia, have the branches expanded laterally into a 

 limb which has a leaf-like appearance. Ruscus aculeatus 

 (PI. 16, fig. 3,) also presentsw inged branches, which have 

 exactly the appearance of a true leaf. In these different 

 cases, we recognise their true nature either by studying 

 the origin of the organs, or by following their develop- 

 ment ; when they begin to enlarge, the woody body, by 

 distending the bark, gradually obliterates these foliaceous 

 appendages, and the winged branches are changed into 

 cylindrical stems. 



CHAPTER IV. 



OF DEPOSITS OF NOURISHMENT, OR THE FLESHY, FE- 

 CULENT, ETC. DEGENERATIONS WHICH MODIFY THE 

 TEXTURE OF ORGANS. 



In the same manner as some organs, taking a more 

 ligneous texture than ordinarily, may be changed into 

 thorns, and thus become the defensive arms of the 

 plant ; so there are other parts which, acquiring a con- 

 siderable thickness, receive into their tissue a large 

 quantity of watery, mucilaginous, feculent, or oily 



t 2 



