1«0 



EXPERIMENT STATION. 



[Jan. 



The difference iu growth may be shown further by the differ- 

 ence in the length of internodes (or joints) in the wood. A 

 large number of measurements were made of the internodes of 

 one-year-old wood, with the following results : — 



Length of Internodes. 



Average 

 (Centimeters). 



Standard Deviation 

 (Centimeters). 



On Americana, 

 On Wayland, . 

 On Marianna, 



9.60 

 10.92 

 15.80 



6.85 

 8.87 

 10.47 



These figures show a much ranker, more vigorous growth in 

 trees on Marianna stocks than on the others. There is also a 

 greater amount of variation. The striking differences in the 

 growth of internodes, however, are again shown most forcibly 

 by representing all the measurements graphically, as is done in 

 Fig. 4. 



This difference in growth comes out in every point where 

 measurements can be taken. For example, the diameter of a 

 large number of branches was measured on two-year-old, on 

 three-year-old and on four-year-old wood. The average measure- 

 ments are shown below : — 



Caliper Measurements of Brandies {Centimeters). 



Three Years. 



Four Years. 



On Americana, 

 On Wayland, . 

 On Marianna, . 



3.92 

 3.90 

 4.76 



5.55 

 5.19 

 6.19 



7.63 

 7.25 

 8.13 



These measurements of the diameter of branches reveal once 

 more the fact that Milton plum trees grow much more vigorously 

 on Marianna roots than on Americana or Wayland. 



