1909.] 



PUBLIC DOCUMENT — No. 31, 



175 



ments were made by Mr. C. S. Pomeroj, then assistant in hor- 

 ticulture in the Massachusetts experiment station, and these 

 measurements form the basis of the detailed comparisons fol- 

 lowing. 



It will be proper to preface these notes further by saying that 

 the measurements herein reported are arbitrarily confined to the 

 one variety Milton, as grafted on (a) Americana stocks, (h) 

 Wayland stocks, (c) Marianna stocks, (d) peach stocks. Other 

 varieties cross-grafted on these same stocks showed substantially 

 the same modifications. 



FoEM OF Leaf. 

 Critical examination shows that the trees were profoundly 

 modified in many directions by the stocks on which they were 

 grafted. One of the characters chosen for special study was the 

 form and size of the leaf. The average size of leaves, taken 

 from several hundred measurements, is shown in the following 

 table : — 



Length and Breadth of Leaves. 



Length Breadth 



(Millimeters). (Millimeters). 



Oa Aniericaua, 

 On Waylacd, 

 On Marianna, 

 On peach, . 



27.20 

 28.22 

 34.02 

 31.56 



These measurements show at once the greater relative and 

 positive breadth of the leaves of trees growing in Marianna 

 stocks. 



In order to show more clearlv the variation in form, — a mod- 

 ification distinctly manifest to the eye, — measurements of 

 breadth were taken not only at the middle of each leaf, but also 

 at distances from the base equal to one-tenth the total leaf length 

 and two-tenths and three-tenths the total length. Similarly, 

 breadth measurements were made one-tenth, two-tenths and 

 three-tenths of the leaf length from the tip. The numerical 

 averages of these measurements need not be given here since the 

 results may be so much more easily understood from the graphic 



