613 



THE FliniO-VASCULAR SYSTEM OF THE APPLE 

 (POME) AND ITS FUNCTIONS. 



Bv D. McAr-pixE, Corresponding Member. 

 (Plates xxi.-xxv.) 



In th<^ case of fleshy fruits, such us the Apple, there is a 

 general impression that the entire edible substance consists 

 of a succulent mass of tissue, without any of the stringy 

 material which occurs in other pai'ts of the tree ; and even 

 Sachs* states that the whole edible substance is composed of 

 fundamental tissue, as distinct from the epidermis, on the 

 one hand, and the vascular bundles, on the other. But when 

 one remembers that the central core of the apple is siir- 

 rounded by a relatively large mass of tissue, which grows 

 and enlarges at a comparatively rapid rate, the necessity 

 will be readily recognised for a framework of some kind for 

 the soft parts ; and there must be vessels or cells of some 

 sort to convey the necessary food to the living and growing 

 tissue. In other words, there must be a skeleton to prevent 

 collapse, and conducting tissue to convey nourishment. 



This is provided for in the fibro-vascular system, which 

 looks very elaboi-ate and complicated as a whole (Fig. 8), but 

 when examined in detail, it is seen to consist of a definite 

 number of strands, which give rise to numerous branches 

 (Fig. 12.) 



General Strnrturc of the Apple. 



The structure of the mature apple will now be dealt with, 

 in so far as it is necessary for the understanding of the dis- 



* Lectures on tlie Physiology of Plants, p. HI. 



