284 Plums and Plum, Culture 



formities are of various kinds, but the commonest is 

 an atrophied or undeveloped pistil. The female or- 

 gans of the flower simply fail to grow. They may be 

 found in the center of the blossom, blackened, de- 

 formed and shriveled. In a few cases certain trees 

 never produce good pistils. There are a few named 

 varieties in cultivation, merely as curiosities, which 

 never have perfect pistils. The Blackman plum, and 

 Mr. Kerr's Mule are of this sort. It is evident that in 

 such cases no fruit can be formed. 



Extensive studies of these defects made at the 

 Vermont Experiment station, however, show that they 

 are seldom of practical consequence. There are usu- 

 ally enough good pistils on any tree of native plums to 

 make a full crop if conditions are favorable for 

 pollination. 



Insufficient pollen. — In some cases it doubtless 

 happens that there is a shortage of pollen, and that 

 pollination fails on that account. This occurs very 

 seldom, however, and practically may be left out of 

 account. 



Difference in time of maturity between the stigma 

 and the pollen. — The stigma is often ready before the 

 pollen is. This is especially true of the Americana 

 plums. This difference in maturity has been observed 

 to be as much as five days. It varies with the locality 

 and the season. It does not seem to be a constant 

 characteristic of any particular varieties. The pollen 

 is sometimes shed before the stigmas are ready for it ; 

 but this occurs so very rarely, according to my obser- 

 vations, that it amounts to nothing. Even when the 

 anthers burst before the stigmas of the same flowers 

 are quite ready, this difference is never more than a 

 few hours; and there seems to be always pollen enough 

 from other flowers on the same tree to effect a thor* 



