366 



Bulletin 181. 



74. — Section of one 

 hud in Fig. 73. 



14: to show the shriveled stamens and pistils. The leaves in this 

 cluster came through all right, but the flowers were injured. The 

 single flower which has expanded is too small and weak to develop 

 into fruit. These winter-injured clusters were common on all varie- 

 ties of pears, particularly Angouleme and Manning Elizabeth, and 

 on some varieties of apples, in the spring of 1899. 



Two forms of winter or spring frost injury to the pistils are seen 

 in Figs. 75 and 76, with a normal blossom for comparison in Fig. 77. 

 A common form of injury is that in Fig. 75, in which the pistil is 



blackened and stunted, having made no perceptible 

 growth during the opening of the flower. These 

 pistils always drop from the tree soon after the 

 petals have fallen. Another and not less common 

 form of injury is that in Fig. 76, in which the pistil 

 has made a partial growth but has no well developed 

 ovary. Unless a careful examination is made, blos- 

 soms like this would not be considered as winter- 

 injured. Of tifty which were tagged, none gave 

 fruit, although several fruits grew to the size of 

 peas. The killing of the pistils is the most common form of winter 

 injury to fruit buds. Some of the native and Japanese plums had 

 as high as 80 per cent of defective pistils last spring, but with their 

 enormous amount of bloom this did not materially decrease the crop 

 of fruit which the trees were able to carry. The Japanese plums 

 bloom so early that their blossoms are liable to be injured by frost 

 in the middle states and south. 



It is thus seen that the injury to fruit blossoms from cold is of 

 all degrees. During the opening of a normal 

 flower, the pistil grows. It is often taken for 

 granted that if this growth occurs the pistil is 

 uninjured ; but it may be that even though a 

 pistil reaches its full size, it may yet be so 

 injured that it cannot develop into fruit. In 

 1899 about ten per cent of the blossom buds of 

 a royal apricot opened fully, like the one in 

 Fig. 72. All of these blossoms appeared to be 

 perfect, with long pistils, plump ovaries and well developed stamens. 

 Yet hardly a dozen fruits set on the whole tree, although the weather 



5. — Catherine apri- 

 cot ; injured pit>til. 



