18 MASS. EXPERIMENT STATION BULLETIN 418 



in the nursery or in the orchard. The growth of the tree may give some indica- 

 tion but is likely to raise more questions than it settles. In some cases, sprouts 

 from the rootstock may prove its identity, but sometimes they make poor growth 

 in the shade of the tree. In most cases, no sprouts appear. With the exception 

 of Mailing III, none of the Mailing stocks sprout from the stock more frequently 

 than do seedling-rooted trees. It is small satisfaction to discover that one has 

 the wrong rootstock after the trees are planted in the orchard. Stock beds and 

 lined-out stocks should be examined and rogued of mixtures. It has been our 

 experience that stray trees sometimes appear in the stock bed and nursery rows 

 and their source is sometimes a mystery. 



All the clonal stocks we have grown can be identified as well as can our culti- 

 vated varieties, but it requires careful observation and considerable study to do 

 so. They can be identified in the stock bed or in the nursery row before the tops 

 are cut following budding. It is best to look at them while in leaf though some 

 can be named quite positively when dormant. They must make at least moder- 

 ately vigorous growth; weak trees do not show varietal characteristics clearly 

 and are always a problem. While it is best to examine lined-out stocks late in 

 the summer just before budding, it can be done after budding but before the 

 leaves fall. However, the discovery of a mixture after the trees have been budded, 

 brings out a situation that is difficult to correct. 



Before attempting to describe certain clonal rootstocks, it is necessary to point 

 out the characters of the plant that are useful in identification and attempt to 

 define the terms used. In the descriptions the characters are treated in the 

 same order as they are here given, 



Growth 



Vigor and type of growth vary with growing conditions. Descriptions must, 

 therefore, be comparative. Some stocks are taller and of larger diameter than 

 others. For instance, Mailing I is always taller than Mailing IV and stouter 

 than Mailing III when all are growing under similar conditions. Some, as 

 Mailing XII, are verj' upright while Mailing VIII makes a spreading or sprawl- 

 ing growth. The growing tips of some stocks are more or less tinged with red, 

 while others are green or yellowish green. 



Internodes 



The internode or the distance between the leaves on the current season's growth 

 is generally shorter than in our cultivated varieties, especially with the more 

 dwarfing stocks. This gives the shoot a more leafy appearance. 



Spurriness 



The clonal stocks show many short stiff growths that do not grow into normal 

 branches. Their presence is objectionable because they interfere with easy 

 budding. While they have value for identification purposes, their number varies 

 greatly with season and cultural conditions; yet their relative abundance on 

 different rootstocks in one stockbed will be fairly constant. 



Bark Color 



The bark color is distinctive but very difficult to describe. It varies with age 

 and growing conditions. Young bark is green, but it soon darkens to some shade 

 of olive, brown, or red, or a blend of these colors. The bark color usually de- 

 scribed is that typical of midsummer or late summer after the most vigorous 

 growth is over and the bark is partially matured. 



