BY D. MCALPINE. 619 



The leaves of the tree are now busy manufacturing starch, 

 some of which will be transported in the soluble form of 

 sugar to nourish the growing fruit, which is, however, able, 

 to a certain extent, to provide for its own needs in this 

 respect. The chlorophyll-containing cells of the hypodermal 

 layer are also producing starch under the influence of sun- 

 light, so that from these two sources — the green leaves, and 

 the green layer of the fruit — abundance of starch is formed 

 in a normal season. This has to be rapidly transported, when 

 the fruit is swelling, from the place of manufacture to the 

 tissues where wanted. The insoluble starch is rendered 

 soluble by means of a ferment, and the use of the innumer- 

 able connected and branching veinlets in the hypodermal tis- 

 sue will now be evident. In the fruit-growing season, there is a 

 great drain upon the plant's resources; and the manufactured 

 starch must be quickly removed, in order to make room for 

 fresh supplies. "The solution of starch is hastened by the 

 continual removal of the sugar produced."* 



But the green apple is not merely a consumer, using the 

 material supplied, for building up its tissues ; it requires to 

 store up material towards the period of ripening, and starch 

 grains are invariably found in the cells of unripe fruit. "The 

 percentage of starch in apples varies entirely with the age 

 of the fruit ; in green apples it may amount to five per cent, 

 or more, while in the completely ripened fruit it is altogether 

 ivanting."t 



The vascular bundles, as a whole, can now be understood. In 

 a transverse section of the stalk just as it enters the fruit(Fig.ll), 

 there are ten vascular bundles, although sometimes two adjoining 

 may become confluent. These, on entering the fruit, spread out 

 out to form ten main trunks with numerous branches, and con- 

 veniently situated about midwav between the skin and the centre. 



• Pfeffer, The Physiology of Plants. Vol. i., p.505. 

 t Browne, " A Chemical Study of the Apple and its Products.' 

 aylvania Department of Agriculture. Bulletin 58. 



