LEAF CHARACTERS OF APPLE VARIETIES. 23 



Which are the Char.\ctertstic Leaves. 



The leaves on any tree can be dmded into two groups: (1) the single 

 leaves coming out on the current season's growth; and (2) the rosette 

 leaves coming out of buds formed the previous season, i.e., on wood of last 

 year's growth. The latter should be discarded, and study and attention cen- 

 tered on the single leaves on the current season's growth. Leaves that 

 have been injured by lice or other insects or by scab spots are of little 

 value for identification purposes. Leaves on shoots in the interior of the 

 tree should be avoided. Study the ivell-developed uninjured leaves usually 

 found along the middle of the season's groivth. Leaves on trees that are 

 poorly nourished are often undersized and yellowish. Such leaves are 

 not typical and should be observed with caution. 



Typical leaves are found on healthy uninjured trees that are making 

 vigorous but not excessive growth. Inasmuch as one requires the leaves 

 of the current season's growth, little progress can be made in leaf study 

 until considerable growth has been made. The most favorable period is 

 from July 1 until October 1. To one familiar with leaf characters this 

 period may be extended somewhat. 



What to Look at. 



To the beginner in leaf study the leaves of all varieties will look alike. 

 Close and repeated observation will reveal differences that are peculiar 

 to the different varieties. It is our purpose here to discuss the various 

 parts of the leaf and how they differ in different varieties. (See Fig. 1.) 



The Petiole. 



The petiole or stem of the leaf is sometimes characteristic of the variety, 

 though it is of minor importance. Wealthy has a rather long, slender 

 petiole, while that of Mcintosh is usually short and stout. The angle 

 which the petiole forms with the shoot on which it grows is often helpful in 

 recognizing varieties. In the Spy the angle is sharp, that is, the leaf is 

 said to be upright; while in the Rhode Island Greening it is broad or 

 spreading. This character is correlated in all varieties with the form of 

 the top. The Spy has an upright head, while the Rhode Island Greening 

 is distinctly spreading. This character of the head or form of the tree is 

 quite well known to fruit growers, but few are aware that in an unknowTi 

 variety the form of the top can be foretold with considerable accuracy 

 from the leaf angles on a one-year whip. 



The Stipules. 



The stipules located at the base of the petiole have a certain value in 



variety identification. They vary in size and shape and in the degree to 



which they persist. In all or nearly all varieties they are likeh' to fall by 



late summer or early fall, especially if there is a good deal of dry weather. 



