Brooks: The Fruit Spot of apples 429 





The lenticels are far more numerous on the blossom half than on 

 the stem half of the apple. This statement is based on actual count 

 as well as on general observations. A square centimeter was 

 marked off on the stem half of an apple and another on the blossom 

 half and the lenticels counted on these areas. By averaging the 

 results secured from ten Baldwins the ratio of seven to four was 

 obtained as that existing between the number of lenticels on the 

 blossom and stem halves of the apple. On Northern Spies the 

 ratio was approximately five to three. 



Hypodermal parenchyma. — Immediately beneath the epidermis 

 are layers of cells that are distinctly different from those more 

 deeply situated. These cells are smaller and more compactly 

 arranged. They are oblong in shape with their greatest diameter 

 parallel to the epidermis. They are rich in chlorophyll and take 

 an active part in the nutrition of the apple. They contain the red 

 coloring-matter of the fruit, which, according to Pick (18), develops 

 from tannin under the influence of sunlight. There is a gradual 

 transition from these cells to the large isodiametric ones that make 

 up the mass of the apple tissue. 



Vascular system. — The close relation of the conducting sys- 

 tem to spot diseases makes a study of the vascular bundles of in- 

 terest in this connection. The general distribution of these could 

 be studied best in frozen apples. With these the soft flesh could 

 be nearly all removed by holding the half of an apple under the 

 current from a laboratory faucet. The remaining portion of the 

 a Pple could be very satisfactorily studied by floating it in water. 

 " an apple is cut into halves perpendicular to the core, ten green 

 spots may be seen arranged in the form of a circle about midway 



If 



between the core and the epidermis (plate 51, figure i). These 

 ar e the large vascular strands of the apple. Smaller branches 

 ar e given off from either side of them. Figure 7, plate 35 is a 

 sk etch of one of these ten vascular strands with the branches that 

 anse fr °m one side of it, i. e., it shows about one twentieth of the 

 Ocular system of an apple. The main branches give off com- 

 paratively few smaller ones before reaching the margin of the sur- 

 zone of cells previously described. Here they branch pro- 



fac 

 fusel 



Usel y and anastomose in a seemingly indiscriminate manner. The 

 VeinIets from one large vein unite with those from another so that 



