4 MASS. EXPERIMENT STATION BULLETIN 403 



The Lenticels: These are the breathing pores, which appear as small dots on 

 the bark. They may seem inconspicuous but are of value in identifying varieties. 

 They vary in number, size, shape, and color in different varieties. They are often 

 more abundant in some parts of the shoot than in others, and the tendency is to 

 consider the numbers in the area where they are most plentiful. They are gen- 

 erally roundish in form, but occasionally a variety may show some elongated 

 lenticels. The color is usually some shade of grayish, but some are more or less 

 yellowish or even almost white. In some varieties the lenticels are even with the 

 surface; in others, they are raised so that they can be felt distinctly with the 

 thumb or finger or detected with a small magnifying glass. 



The Leaf Blade: The blade of the leaf is of the greatest importance in identi- 

 fying varieties, and the description is therefore given in detail. Size is a varietal 

 characteristic, although it may be affected somewhat by the vigor of the tree. 

 The blade may be flat, or the two halves may be more or less folded upward. 

 The midrib may be straight or curved downward (reflexed). In some varieties 

 the leaf edge shows no waving whatever; in others, it may be coarsely or finely 

 waved. Apple leaves are usually oval; but sometimes they are more or less ovate, 

 which means that they are narrower toward the tip than at the base of the leaf; 

 they may be broad, or they may be narrow. The color is always some shade of 

 green; but it may vary from light to dark green, or it may be slightly yellowish 

 or bluish green. In some varieties the leaves are rather upright, forming a narrow 

 angle with an upright-growing branch; in others they may be spreading; and in 

 still others, drooping. This leaf angle is generally correlated with the branch 

 angle, so that the form of the tree can be foretold with considerable accuracy 

 from the leaf angles on a one-year whip. 



The Serrations: The notches along the leaf edge vary with different varieties 

 and are of great value in identification. They may be very sharp or very dull, 

 but in most varieties they are intermediate. They may be large or small — 

 frequently referred to as coarse or fine. Sometimes the serrations are all alike in 

 size and are described as regular; in other varieties they vary and are called ir- 

 regular. If the spaces between the serrations are pronounced, the serrations are 

 said to be distinct. 



The Surface: The light reflection from the upper surface of the leaf varies 

 with the variety. Some leaves are more or less shining; others dull. The surface 

 texture of the leaf may be smooth or rough. The pubescence, which varies in 

 amount, is most apparent on the under side of the leaf, and where abundant 

 gives a grayish color to the foliage. 



Following the technical description of a variety, the prominent characteristics 

 are given — those which have come to be relied upon for recognizing a variety. 



Years of experience have shown that certain varieties are likely to be confused 

 in the nursery and consequently mixed in the orchard. Therefore, the descrip- 

 tion is completed by a statement of how the variety differs from those with which 

 it is most likely to become mixed. 



