620 PIBKO-VASCULAR SYSTEM OF THE APPLE, 



The earliest branching and the most direct course is towards the 

 carpels and the seeds, then the flesh is supplied by numerous 

 diverging branches which unite to form a network of vessels, and 

 finally terminate, beneath the skin, in a perfect maze of the most 

 delicate forked veinlets. So richly is the apple supplied with a 

 connected system of vascular bundles, that it would be difficult 

 to find an area of any size without them. 



The reason for this is evident, since the developing fruit must 

 be richly supplied with food-materials to maintain the rapid 

 growth. The water, containing mineral matter in solution, the 

 so-called " crude sap," is conveyed by the wood-portion of each 

 bundle with its vessels and tracheids. The solution of organic 

 food-material, the so-called " elaborated sap," passes along the 

 bast-portion with its sieve-tubes and associated cells; and by means 

 of numerous cross-connections between the two kinds uf tissues, 

 there is a blending of the " crude" and "elaborated " saps, which 

 results in the formation of proteid substance; and this, in contact 

 with the living protoplasm, becomes converted into the living 

 substance itself. 



The vascular system must not be conceived of as a vast network 

 of tubes conveying food-material to a definite terminus, but as 

 being tapped on the way by living tissues wherever growth is 

 going on, or storage is required. The movement of the food- 

 materials takes place in whatever direction supplies are wanted, 

 and, even in the same cell or vessel, there may be a flow in opposite 

 directions at the same time. 



The Skeleton. 



The apple starts as a very small fruit, but gradually grows to 

 a good size, and therefore requires a framework to support the 

 fleshy portion. There is great variation in the size and weight of 

 apples. Home Beauties have reached 19ozs., and Rymers 22ozs. 

 in a Victorian orchard during the past season; but the heaviest 

 known to me grew on a six-year old tree in the same orchard. It 

 was a Munroe's Favourite, green when picked, and weighing 

 2 lbs. 2 ozs. Such a mass of pulpy tissue would collapse by its 

 own Aveight, unless there were some means of strengthening it. 

 The distended cell-walls of the tissue itself would tend to stiffen 



