36 SYSTEMATIC POMOLOGY 



differs more or less in all t'l-uits. I'ossihly wcvy variety bears 

 leaves of a distinctive color and if llic means of studyinj^ color 

 were more refined it wonld be possildc to classify fi-uits by color 

 of leaf alone. In several fruits, there are distinct correlations 

 between leaf and fruit color. Thus, there is more yellow in the 

 ribs and veins of leaves and stipules of yellow-fleshed peaches 

 than in white-tieshed sorts. In apples which bear j^reen-colored 

 fruits, the leaf is a pure green ; in those which have red fruits, 

 the leaves are darker and have a tinge of blue or purple or 

 sometimes are distinctly reddish. 



58. Stipules. — The small and narrow stipules of pears and 

 apples are hardly worth attention in classification, but they 

 may be utilized in distinguishing some of the drupe-fruits, espe- 

 cially in the cherry where they have considerable value in sepa- 

 rating closely related varieties. Stipules which appear with the 

 first leaves of the cherry are small and drop before the fruit 

 ripens, but those of later leaves are large, borne in pairs, and 

 remain until the fruit ripens. The time of dropping varies 

 greatly with the variety. Stipules of cherries are variously 

 toothed and bear glands of several colors and shapes which are 

 characteristic. 



59. Leaf-glands. — On the leaves, stipules, and petioles of sev- 

 eral hardy fruits there are small protuberances, usually organs 

 of secretion, called glands. Much use can be made of these 

 glands in classifying peaches and currants. Their presence or 

 absence, size, color, position, number, and whether stalked or 

 sessile must be noted. Two shapes are most common in peaches : 

 globose, those which are small globes ; and reniform, those which 

 are kidney-shaped. The most characteristic glands of peaches 

 are found toward the end of summer. Varieties of peaches with 

 glandless leaves are reputed to be more susceptible to mildew 

 than those bearing glands; on the other hand, they are said to 

 be more resistant to leaf-curl. The yellow resinous dots on the 

 under surface of the black currant are secreting organs akin to 

 glands, which on the stalks of buds and on the bud-scales of 

 this fruit are even more glandular. 



60. Leaf-lobing in grapes. — In classifying grapes the lobing 

 of the leaf is a very uniform character within species, although 

 Vitis Munsoniana and V. rupestris have leaves which are not 



