PEACH YELLOWS. 247 



but there is a marked piolepsie. These shoots may appear upon any part of 

 the tree, and of ten are developed numerously upon the trunk and main limbs, 

 from obscure or adventitious buds. Most commonly I found them growing 

 out close together upon the upper side along the entire length of a main limb, 

 or of several such limbs, giving the interior of the tree-top a very peculiar 

 appearance, entirely unlike that caused by any other disease. Where these 

 shoots appeared numerously upon a limb they were frequently unbranched 

 and pnly a few inches in length, at least in July and August. More often, 

 especially late in the season, I found them branched. In some instances these 

 diseased shoots and their branches were very long and willowy. Often the 

 leaves also suggested the willow. 



The manner of this branching was to me a striking peculiarity, and one 

 which I had never seen mentioned in connection with the disease. There is, 

 as we have' seen, an excessive duplication of shoots. Shoots, it is true, are 

 likely to occur to some extent upon the trunk and main limbs of all robust 

 trees, but never in such numbers, nor branched in the manner to be described, 

 nor with such a starved appearance. Not only are the shoots dwarfed and 

 sickly but their growth is extremely hurried, i. e., in their leaf axils they 

 develop buds which the same season give rise to diminutive branches, and in 

 turn these branches in the same way give rise to others. Very often I found 

 that three sets of branches, and in some instances four and even five, had devel- 

 oped on these shoots as the results of a few months' growth. These branchea 

 are very clearly shown in some of the photographs accompanying this report, 

 as may be seen by comparing them with contemporary healthy growths. 

 The tissues of these branches are very poorly developed and their buds are 

 diminutive and very often dead before they enter the winter, differing in 

 these respects from the few witch brooms I have had opportunity to examine^ 

 Moreover, there is never any hypertrophy of the branches which bear them. 

 The foliage of such shoots is often blanched or pale yellowish green, and 

 never of a vigorous green. It is abundant but very much dwarfed, the best 

 developed leaves being frequently less than 3 inches long and propor- 

 tionately narrow, and many of the smaller ones being less than an inch in 

 length, while full-grown, healthy leaves are from 6 to 9 inches in length by 

 1^ to 2 inches in breadth. Frequently by failure of the internodes to prop- 

 erly lengthen and by the excessive production of branches the growth 

 becomes considerably tufted. 



As autumn passes away these diseased shoots manifest no signs of prepara- 

 tion for winter (see Photo. V). There appears to be something analogous to 

 what in animals would be called a lack of innervation. The ordinary Junctions 

 of the plant are disturbed or set aside altogether. Growth goes on without 

 much reference to the needs of the plant or the time of the year, and is at the 

 same time excessive and imperfect. In late October and in November, when 

 healthy trees had dropped their leaves and were ready for winter weather, 

 such shoots were still growing. 



Although these diseased shoots appear to be a secondary symptom, yet they 

 may follow the diseased fruit speedily. In autumn I saw them on many trees 

 which were not diseased the previous year, or at least showed no external 

 manifestation of disease^ and in nearly all such cases they were secondary/ 

 growths from obscure buds, first appearing in June or July or later in the 

 year, the primary, terminal, or spring growth being usually the picture of 

 health, as regards both branches and foliage. However, this was not uniform- 



