138 PEOPAGATION OF PLANTS. 



blooming, the flowers appearing with those of the former, 

 although the Red Maple usually blooms several days 

 earlier than the Negundo. The next season I found 

 several seedling Negundo Maples coming up under a 

 Pine tree near by. These were transplanted, and last 

 spring, 1886, one of them bore seed, a pistillate like 

 the parent. While I cannot say positively that the 

 flowers of the Negundo Maple were pollinated or fertihzed 

 by those of the Eed Maple, still the facts in the case 

 point strongly that way. The seedlings produced in 

 this anomalous manner do not appear to be hybrids, but 

 this point cannot be definitely determined until plants 

 are raised from the present race of seedlings, and even 

 then the influence of the pollen-bearing parent may re- 

 main hidden through several generations and afterwards 

 appear when and where least expected. It is not at all 

 improbable that the presence of non-related pollen may 

 excite development in the pericarpic organs, and if this 

 be true we can the more readily account for the produc- 

 tion of fruits with abortive seeds — the stigma having 

 been pollinated, but the pollen tubes having failed to 

 fertilize the ovules. 



The excitability of plants due to the presence and in- 

 fluences of pollen has long been observed by the cultivators 

 of the Hop plant, the quantity of lupuline deposited in 

 the strobiles or female catkins being far more abundant 

 when there are staminate or male plants present than 

 when they are absent. It is also well known that 

 among our larger fruits we have seasons of scarcity and 

 of abundance, and these variations cannot be attributed 

 to changes in the climate or to age, maturity or non- 

 maturity of the trees, for planting is going on continually, 

 so all sizes, ages and varieties are represented in our 

 orchards, still all seem to readily acquire the habit of 

 bearing full crops every alternate year or at longer inter- 

 vals. That this unity of action among fruit trees, as 



