40 BOARD OF AGRICULTURE. [Pub. Doc. 



with pollen from a distinct species, they are sterile in all 

 possible degrees, until utter sterility is reached. We thus 

 have a long series with absolute sterility at the two ends ; at 

 one end due to the sexual elements not having been suffi- 

 ciently differentiated, and at the other end to their having 

 been differentiated in too great a degree, or in some pecul- 

 iar manner." 



The difficulties in the way of successful results through 

 hybridization are, therefore, these : the difficulty of effect- 

 ing the cross; infertility, instability, variability, and often 

 weakness and monstrosity of the hybrids, and the absolute 

 impossibility of predicting results. The advantage to be 

 derived from a successful hybridization is the securing of a 

 new variety which shall combine in some measure the most 

 desirable features of both parents ; and this advantage is 

 often of so great moment that it is worth while to make 

 repeated efforts and to overlook numerous failures. From 

 these theoretical considerations it is apparent that hybridiza- 

 tion is essentially an empirical subject, as the results are 

 such as fall under the common denomination of chance. 

 And, as it docs not rest upon any legitimate function in 

 nature, we can understand that it will always be difficult to 

 codify laws upon it. 



Among the various characters of hybrid offspring, I pre- 

 sume that the most prejudicial one is their instability, their 

 tendency still to vary into new forms or to return to one or 

 the other parent in succeeding generations ; it is difficult to 

 fix any particular form which we may secure in the first 

 generation of hybrids. At the outset, we notice that this 

 discouraging feature is manifested entirely through the fact 

 of reproduction, and we thereby come upon what is perhaps 

 the most important practical consideration in hybridization, — 

 the fact that the great majority of the best hybrids in culti- 

 vation are increased by bud-propagation, as cuttings, layers, 

 suckers, buds or grafts. In fact, I recall very few instances 

 in this country of good undoubted hybrids which are propa- 

 gated with practical certainty by means of seeds. You will 

 recall that the genera in which hybrids are most common are 

 those in which bud-propagation is the rule; as begonia, 

 pelargonium, fuchsia, gladiolus, rhododendron, roses, and 



