THE PROPAGATION OF APPLE TREES. 79 



seen, and the onlj' time a question arises is when a root appears just at 

 the Hne of union. As a matter of safety in the main investigation, such 

 trees have been counted as not rooted. After cutting away the seedhng 

 root the trees are replanted and budded during the summer if desired, 

 and if the}' have not been already. At the end of one or two years we 

 have a satisfactory tree established on its own roots or the roots of another 

 named variety. 



Relation of the Variety to Root Formation. 



At the start of this work the sole purpose was to obtain trees on known 

 roots for purposes of orchard and laboratory investigation of the inter- 

 relation of root and scion. It soon became evident that there were great 

 varietal differences in the readiness with which roots were thrown out 

 from the scion, and tests have been made of over 150 different varieties 

 and species to measure their rooting ability. These tests have extended 

 over a period of seven years. Some varieties have been tested only once, 

 others two or more times, and some have been tested six times, and all 

 in varying numbers, as shown in Table 2. Most of the scions have been 

 taken from bearing trees or from those that have since come into bearing. 

 A record has been kept of each lot separately, so that in a few cases, 

 where the parent tree proved to be misnamed, the necessary correction 

 has been simple. A few lots of scions were secured from nurseries; those 

 were carefully examined for mixtures of varieties, and, so far as possible, 

 compared with trees known to be true, and with printed descriptions. 

 There is no more excuse for mixtures of trees in the nursery row than for 

 mixtures of fruit in the barrel. All cases of doubtful identity have been 

 thrown out, and it is thought that there is little chance of error in the 

 varieties given in the table. 



Individual lots of the same variety have differed widely in the per- 

 centage rooting, internal conditions in the scion or environmental con- 

 ditions, or both, e\adently playing an important role in root formation. 

 Some of these will be discussed later. 



I 



