THE SCIENCE AND PEACTICE OF CEOSS POLLINATION. 467 



vidual in the vegetable kingdom corresponds to the mule in the ani- 

 mal kingdom. The word "crossing," however, is often used as a 

 convenient term, meaning both crossing and hybridizing. Over 

 fifty years ago Lindly said : "Hybridization is a game of chance 

 played between men and plants." In other words, there is no means 

 of foretelling what the result will be when plants are crossed. Espec- 

 ially is this true with our cultivated fruits, as all are more or less of 

 mongrel ancestry. 



The main benefit in hybridizing plants is to break up the fixity of 

 type. Then when this is done the seeds of these hybrids should be 

 planted largely to give an opportunity for the forces of heredity to 

 assist themselves. Burbank, of California, and Theodore Williams, 

 of Nebraska, find, in improving plums, that hand crossing is of use 

 mainly at first to break up the fixity of type. After the hybrid plum 

 trees are obtained they are grown intermingled close together in 

 nursery rows, and other sorts are top-grafted in the limbs. The pits 

 grown are then planted and nature has been given a chance. The 

 result will be : First — If the flower is self- fertilizing the seedlings 

 may nearly or quite revert to one or the other of the parents or to 

 some ancestor further tack. Second — If bees or the wind have 

 carried foreign pollen, still greater tendency to variation has been 

 introduced. 



Crossing and hybridizing I regard as short cuts in the work of 

 improving fruits. It is a means of hastening the process of evolu- 

 tion by introducing new elements of variation. 



In 1901 the writer grew at Brookings 499 seedlings of the Com- 

 pass, the well known hybrid sand cherry originated by H. Knudson, 

 of Springfield, Minnesota. The Compass, by the way, is very fruit- 

 ful and hardy at Brookings and proves worthy of a place in the 

 home garden, furnishing an abundance of fruit just ahead of our ear- 

 liest plums. These seedlings show remarkable variation, some ruuning 

 back to the sand cherry and others approaching closely the plum in 

 foliage. Some seedlings were selected with root intermediate be- 

 tween the red of the sand cherry and the brown yellow of the plum 

 and planted this spring as one year seedlings. Many of them flowered 

 but did not fruit, as they were transplanted. C. G. Patten, of Charles 

 City, Iowa, has obtained very interesting results from seedlings of 

 the Brier Sweet crab, a hybrid of the Siberian crab with the Bailey 

 Sweet. The experiments of Peter M. Gideon indicate, however, 

 that long keeping capacity cannot be expected from any of the Si- 

 berian crab hybrids. The amateur and the busy nurseryman can 

 perhaps do the best work in crossing fruits by top-grafting largely, 

 as done by Burbank and Williams, and sowing the resultant seeds. 



