324 Harris M. Benedict 



TABLE 41. Relation of Size of Vein Islets to Age in Acer saccharum Marsh 



Diameter of trunk (in centimeters) . . . . 



2.5 



45;9 



61.2 



Number of intersections in 2 centimeters 



50 



74 



90 



TABLE 42. Relation of Size of Vein Islets to Age in Queroxjs velutina Lam. 



Diameter of trunk (in centimeters) 



2 3.8 



76 



Number of intersections in 2 centimeters 



50 58 84 







TABLE 43. Relation of Size of Vein Islets to Age in Platanus Occidentalis L. 



Diameter of trunk (in centimeters) 



5.1 



10.2 



20.6 



45.6 



Number of intersections in 2 centimeters .... 



50 



64 



68 



74 



TABLE 44. Relation of Size of Vein Islets to Age in Fsaxinus amf.ricana L. 



Diameter of trunk (in centimeters) 



1.3 



30.6 



Number of intersections in 2 centimeters 



40 



80 







Size of vein islets in leaves of several varieties of fruits propagated 



by cuttings 

 If age affects meristematic tissue in seed-producing plants, the cells 

 of the scions used in propagating certain varieties of fruits must be affected. 

 Unless the process of grafting and growth on seedhng stocks restores 

 the youthful condition of the protoplasm of the scion, its leaves should 

 show a size of vein islets typical of the time that has elapsed since the 

 variety originated from seed, not of the time since the graft was made. 

 The application of this venation test in order to determine the physiological 

 condition of present cultivated varieties is most important, but Ues beyond 

 the limits of the present paper. However, a few preliminary tests were 

 made of the relative sizes of vein islets in several varieties of cultivated 

 grapes that have been in existence for different lengths of time. Through 



