1916] HORTICULTURE. 237 



weeks ahead of the less hardy sorts. The hardier varieties function during the 

 growing season with a smaller amount of water in their tissues. During a spell 

 of very severe weather they retain their more concentrated cell sap and are 

 not dried out so readily by the continued cold. By taking notes on maturity 

 and making tests to determine the rate of transpiration and the freezing point 

 of the cell sap, the author believes that a pretty accurate idea of the tree's 

 hardiness can be obtained. 



Studies of the structure and composition of the wood suggest that there is 

 some correlation between the thickness and structure of the bark and the rate 

 of evaporation, although the figures obtained from a large number of examina- 

 tions are not conclusive. In some cases the maximum thickness of the bark of 

 the more tender varieties exceeded the minimum thickness of bark of the 

 hardier varieties. The amount of stored food contained in the twigs appeared 

 to bear some relation to hardiness, although exceptions were noted. Observa- 

 tions relative to the size of the blossoms indicate that none of the varieties pos- 

 sessing large size and thickness of petals is tender. On the other hand, hardy 

 varieties do not always have the thickest petals. Tests made relative to density 

 of wood, although not conclusive, indicate that there is some correlation between 

 density and hardiness. 



Freezing tests were conducted to determine, if possible, the temperature at 

 which the various varieties would be injured under a given condition and also 

 to determine the relation between the moisture content and the ability of the 

 twig to withstand cold. The results secured with a number of varieties are 

 given. In general the twigs were found to be either killed or seriously injured 

 when suddenly subjected to a very low temperature, even though it was for a 

 sliort time. A longer period of moderate cold slightly injured the hardier varie- 

 ties and killed most of the tender varieties. 



The relation of climate to varieties of apples, R. M. Winslow (Proc. Soc. 

 Hart. ScL, 11 (1914), pp. 137-148). — The author presents data showing the main 

 features of the growing seasons of dilTerent sections of British Columbia, in- 

 cluding temperature and rainfall observations and notes on the adaptability of 

 the more important varieties of apples to climatic conditions in the different 

 sections. 



A preliminary consideration of one phase of meteorological influence on 

 plants, indicated by hand pollination of several commercial varieties of 

 apples, W. F. Fletchek {Proc. Soc. Hort. Sci., 11 {1914), pp. 116-119). — During 

 the 6-year period, 1905 to 1910, the author conducted hand pollination tests in 

 an orchard in the Shenandoah Valley with several commercial varieties of 

 apples in different combinations of meteorological conditions. The results 

 from this work led him to the following conclusions, which are here presented 

 to indicate a line of research which has received little attention : 



" The sterility or fertility of apple blossoms depends largely upon local con- 

 ditions. In this statement due allowance is made for the tendencies of dif- 

 ferent varieties toward light or heavy crop setting character or productivity. 

 The affinity between two varieties is governed by local conditions immediately 

 attendant on pollination. Periods of rapid evaporation, that is, high tem- 

 peratures, strong winds, and dry air at the time of receptivity of the stigmas 

 are detrimental to the setting of fruit. The shock or the effect of undue ex- 

 posure to the pistils previous to their natural opening or at the time of 

 receptivity is so great and varies so much under slight changes of atmospheric 

 conditions as to negative all comparative work in hand-manipulated cross 

 pollination." 



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