THE PEACHES OF NEW YORK 75 



having the same upper layer of long cells, but with much more heavih- 

 cutinized walls. A study of the transitional forms indicates that the 

 glands are merely modified leaf spines. 



" The leaves with reniform glands are apparently the highest type 

 and the glandless leaves the lowest, with the transition through the globose 

 type. In support of this view is the fact that whenever typically glandless 

 leaves become possessed of glands they are always of the globose type. 



" The serrations of the glandless leaves are very strikingly different 

 from those on a leaf with glands. The former leaves are deeply and doubly 

 serrate, while the margins of the latter are always single and crenate- 

 Almost invariably, when glands develop on a normally glandless leaf, the 

 serrations are transformed to crenations, indicating that there is a very 

 close correlation between the glands and the crenations on the edges of the 

 leaves." 



The French pomologists, Poiteau and Turpin,^ seem to have first 

 made note of the glands in describing peaches, recording their discovery 

 by M. Desprez in the nurseries at the Luxembourg in 1810, after which, 

 for a half-century, French, English and German pomologists regarded 

 them as an infallible means of distinguishing varieties. But, by the middle 

 of the Nineteenth Centur}', classifiers began to give them up because of 

 their variability on leaves of trees of the same variety or even on the same 

 tree. Even Darwin made note of their insufficiency in taxonomic work.^ 

 Now, no one familiar with any considerable number of varieties of peaches 

 would attach very great importance to glands in a system of classification. 



The flowers of peaches are very characteristic, helping to delineate 

 the groups in the several classificatory schemes of various pomologists and 

 being ample to identify not a few varieties. Peach-flowers differ in time of 

 appearance; in length of blooming-season; they may be large, medium or 

 small; pink, rose and rarely white; borne on pedicels of varying length, 

 thickness, color and pubescence; and both the floral and reproductive 

 organs have modifications of their several structures. The size, color and 

 shape of peach-flowers are well shown in the first six color-plates. In 

 some species of Prunus, as some of the plums, the reproductive organs 

 differ greatly in ability to perform their functions, but the blossoms of 

 edible peaches are seemingly always self-fertile and there are less often the 

 mal-formations found in the reproductive organs of some plums. 



A well-marked correlation ^ between the color in the inside of the 



Trait. Arb. Fr. 35. 1807. 



Darwin .4ms. and Ph. Dottiest. 2nd Ed. 2:217. 1893. 



Hedrick, U. P. Science 37:917. 1913. 



