THE RECIPROCAL INFLUENCES OF STOCK AND CION 581 



Some grape stocks cannot grow fast enough to supply some cions; the 

 sand cherry cannot be developed by a vigorous top to the size necessary 

 for the successful support of a rapidly growing plum. If the implied 

 effect of stock on cion be admitted, limitation in that of cion on stock is 

 obvious. 



Distribution and Character of Roots. — Possibly because the root 

 systems of nursery plants come under observation much more than 

 those of the same plants once they are set in orchard or vineyard, there 

 is considerable evidence of an effect of cion on stock in young fruit plants. 

 Nurserymen frequently identify certain pear or apple trees by their 

 root systems, though all are on seedling stocks. Hovey,'"" however, 

 himself a nurseryman, indicated that this could not be done in all cases; 

 some strong growing varieties, he stated, would have strong, and weak 

 growers such as Winter Nelis would have correspondingly weak, root 

 systems. It is stated that the roots of trees grafted with Siberian Crab 

 " generally run down more than those of other trees. " ^''*' 



Murneek^^^ states: "Upright growing varieties of apples of the 

 Russian type, for instance, will form a correspondingly deep growing 

 root system while those of the Winesap type will be flat and shallow. 

 This can be extended even to particular varieties. The Red Astrachan, 

 Oldenburg, Fameuse, for example, form each a characteristic root system 

 of its own. In this connection, Shaw believes 'that the size or stoutness 

 of the main branches is positively correlated with the size of the main 

 roots and angle of the branch with the angle of the main roots and the 

 axis of the tree. In many individual cases this correlation is obscure, 

 yet careful observations with large numbers of trees will reveal it.' " 

 Bailey^ stated that Northern Spy and Whitney tops make the roots 

 of the stock grow deeper than usual. 



Waugh,!^^ discussing plum propagation, reported:". . . Stoddard 

 tops seem to give some of the curved tap-root character of the Americanas 

 to all the stocks on which they grow. . . . One interesting point was in 

 the way in which Stoddard tops induced a conspicuous branching of the 

 root system when worked on peach. With other varieties the peach 

 gave almost always a clean, unbranched tap-root. The weak growth 

 of Green Gage naturally served to induce only a weak growth in most 

 of the stocks on which it was worked; while the rampant growth of 

 Chabot had exactly the opposite effect. The strongly branching root 

 systems found on Chabot trees were probably due in part to the energetic 

 way in which the foliage acted during the growing season. Marianna 

 stocks, which seemed to be uncongenial to Milton, giving only a poor 

 union, made very little growth when grafted with Milton scions. No 

 other case was observed in which Milton appeared to have any influence 

 on its stock. Newman seemed to influence all stocks in the way of 

 giving off more secondary roots. Nearly all stocks when grafted with 



