82 



MASS. EXPERIMENT STATION BULLETIN 190. 



Grafts have been made of twelve varieties of Siberian crab apples, but 

 only those of Transcendent are reported in this paper, owing to some 

 uncertainty in the correctness of the variety names. However, it may 

 be said that they show a range in rooting percentages from zero to 96 

 per cent, being in this respect like the varieties of the common apple. 



Tests have been made of a number of forms of our native apples. The 

 names under which they were received and the sources were as follows : — 



Pyrus angustifolia, 

 Pyrus coronarius, 

 Pyrus coronarius, 

 Malus coronarius, 

 Malus glaucescens, 

 Pyrus iowensis, 

 Malus platycarpa, 

 Pyrus iowensis, 

 Soulard Crab, . 



Arnold Arboretum, Boston, Mass. 

 Arnold Arboretum, Boston, Mass. 

 Prof. W. H. Chandler, Ithaca, N. Y. 

 John Dunbar, Rochester, N. Y. 

 John Dunbar, Rochester, N. Y. 

 Prof. L. Green, Ames, Iowa. 

 Arnold Arboretum, Boston, Mass. 

 D. S. Lake, Shenandoah, Iowa. 

 Prof. L. Green, Ames, Iowa. 



These were grafted and planted in the usual manner and dug after 

 two seasons' growth. The numbers varied from 5 to 104 of each form. 

 No tree in the entire collection showed any signs of throwing out roots 

 from the scion. 



Trees of certain varieties failing to root from the scion during the 

 seasons of 1915-16 were replanted in the spring of 1917. They were 

 moderately strong whips, and were planted about a foot deep so as to 

 cover several inches of the stem. The purpose was to secure additional 

 trees on known roots, and to see if such trees would root more or less 

 freely than newlj^ made grafts. The results are shown in Table 3. The 

 first column gives the number of trees replanted, and the second column 

 the per cent rooting from the scion. For purposes of comparison the 

 per cent rooting from the fu'st planting of these varieties is given in the 

 third column. Only in the case of Northern Spy is the percentage ma- 

 terially lower in the reset trees than in newly planted grafts. In most 

 cases there is a materially higher proportion rooting from the scion. 

 The replanting was on the same plot of ground. The difference may be 

 due to more favorable weather conditions or other environmental causes, 

 but it seems reasonable to suppose that the larger, stronger trees were 

 better able to throw out roots. As a practical means of getting trees on 

 their own roots by the nurse-root method, it would seem wise to replant 

 those failing to root on the first trial. 



