19161 HORTICULTURE. 645 



injur J' to the root sj'stems. In some cases there has been a very marked correla- 

 tion between the amount of fire blight and the rate of growth. The greatest 

 damage has occurred uniformly on the trees making the most growth. In view 

 of the fact that weakly growing trees have also been attacked, it appears that 

 it is the intermediate growth that is most resistant to this disease. 



With regard to color in apples the author concludes that the red colors in 

 apples are developed primarily by sunlight m the later stages of maturity. 

 Hence conditions favoring either of these factors, such as late picking, open 

 pruning, long growing season, sparse foliage, fully developed fruit, light soils, 

 or sod culture, will increase this color, while all opposing conditions will de- 

 crease it. By a proper utilization of one or more of these conditions it is be- 

 lieved that the customary harmful effects on color of heavy tillage or too much 

 nitrogenous fertilizer may generally be overcome. 



The size of the fruit is determined chiefly by the moisture supply, hence the 

 cultural methods that conserve moisture most efficiently will normally produce 

 the largest fruit. Other influences of importance are the number of fruits on 

 the tree, supply of plant food, and the temperature and length of the growing 

 season. 



Starch in apple trees, W. A. Peice (Ohio Jour. Set., 16 (1916), No. 8, pp. 

 S56-359). — An experimental study of the storage and migration of starch in 

 apple trees is reported. 



The author finds in substance that " during the dormant period starch reserve 

 is stored in the living cells of the pith, wood parenchyma, and medullary rays 

 of the apple. With approach of spring, starch is found in the tissues of the 

 bark, appearing first in the phelloderm and collenchyma. As the leaves begin 

 to appear starch begins to disappear from the various tissues in order as fol- 

 lows : Bark, wood parenchyma, rays, pith. It is used first from the youngest 

 wood of the branches in the top of the tree, later from the lower portions of 

 the tree, and finally from the roots. A portion of the starch reserve may never 

 be used in the growth of the tree, but remains behind to be included in the heart- 

 wood, where it remains indefinitely and renders the wood susceptible to decay." 



Stock influence upon vintage quality and other characters of apples, B. T. 

 P. Bakkee {Vniv. Bristol, Ann. Rpt. Agr. and Hort. Research Sta., 1914, PP- 

 117-127). — The results are given of analyses made in 1914 of fruit juices from 

 apples growing on different stocks. The data secured confirm the conclusion 

 previously arrived at as to the negligible effect of the intermediate stock on 

 vintage quality (E. S. R., 33, p. 240). 



Crown g-all and resistant stocks, C. O. Smith (Cal. Citrogr., 1 {1916), No. 

 9, p. 14, fig. 1). — Studies are being conducted at the California Citrus Experi- 

 ment Station with the view of securing resistant stocks for stone fruits. 



Tabular results are here given showing the representative resistant and 

 susceptible species and varieties in the various classes of stone fruits which 

 were subjected to the crown gall by actually inoculating the rapid-growing twigs 

 and branches with pure cultures. Among the almonds inoculated no marked 

 resistance has been found. Stocks of the Domestica and Damson types of 

 plums and certain Asiatic types of apricots showed the strongest resistance. 

 The Golden Beauty variety of Prunus hortulana has shown suflicient resistance 

 to be used as a stock for native plums. Among other American species, P. 

 pumila, a dwarf stock used to some extent in the Middle West, was also strongly 

 resistant. 



The Japanese mountain cherries, wild forms and cultivated races, M. 

 MiYosHi {Jour. Col. Sci. Imp. Univ. Tokyo, 34 (1916), Art. 1, pp. 175, pis. 23).— 

 A systematic study of the wUd and cultivated forms of Japanese mountain 

 cherries, including descriptions of species and varieties. The descriptive text 



