HYBRIDS. 147 



is used as the pollen or the egg cell plant. The resultant hybrids 

 will be nearly identical in dominant character. This has been 

 shown in crossing Wolf on Rollingstone and the reverse ; also 

 the Brittlewood, by Mr. Williams. No. i is the product of Quak- 

 er pollen on Harrison's Peach, No. 2 the reverse. The only prom- 

 inent difference in fruit is that one matures about a week later. 



The character of the mule form of fruits, or such hybrids as 

 are not fertile, cannot be predicted because we have no means of 

 knowing what combinations have formed the pollen cells or the 

 egg cells of the parent. This is especially true of the outward or 

 visible characters, such as size, form, color, &c. It follows that 

 the cross-bred may resemble one of its pure parents, so as to be 

 practically the same. It may present an intermediate between 

 the two parental forms, or it may be nearer to one or the other 

 in any degree, or it may present some form quite different from 

 either parent, or it may revert in appearance to some former 

 type. 



In regard to the primary influence of pollen on the character 

 and appearance of fruit : There are some well authenticated 

 cases of such influence on strawberries, apples and other fruits. 

 No elaborate experiments have been conducted to establish a law 

 or rule by which this has been accomplished. The pollenizing 

 process has been questioned by some and attributed to sport or 

 bud variation. In the crossing of peas by Mendel and others, 

 it has been found that the influence of foreign pollen can be de- 

 tected immediately after fertilization in the form of the seeds and 

 cotyledons, but other characters remain invisible till the next 

 generation is produced. 



From these facts we may see that there may be any num- 

 ber of pure characters associated in one organism, and each 

 character is capable of being dissociated or replaced by its con- 

 trary, the resultant being a distinct unit character — unit char- 

 acters being of such a nature that any one of them is capable of 

 being displaced or of displacing alternative characters, taken 

 singly. These unit characters have been named allelomorphs, or 

 pairs of contraries, and while we know that one may be displaced 

 we do not know that pairs can be displaced by other pairs, these 

 being alternative to each other in the constitution of the germ 

 cells according to a definite system. 



Dominance is merely a phenomenon incidental to specific cases, 

 between which no other common property has been perceived. 

 In blended inheritance we have no dominance ; in alternative 



