146 MINNESOTA STATE HORTICULTURAL SOCIETY. 



naturally cross reciprocally and have done so from the beginning, 

 which produced varieties in endless confusion. No one can pre- 

 dict with any certainty what the progeny will exactly be by the 

 crossing of two varieties. In some cases the pollen cells unite or 

 blend with the egg cells of the pistillate plant, in which case the 

 product is a new creation and may be entirely unlike either par- 

 ent, and if these pollenize themselves the after progeny will 

 prove constant in character. Another principle : If the plants 

 of both parents have similar dominant characters, the character 

 of the dominants will be perpetuated if the progeny be pollen- 

 ized by the parent pollen. In some cases the pollen and the egg 

 cells do not blend, but either one may be vivified when brought 

 in contact, and the resulting progeny will be more or less the 

 counterpart of the dominant plant, so much so that only the 

 character of the one parent can be distinguished; but even this 

 progeny may invisibly retain a recessive character and appear 

 like the other parent after several generations, either by accu- 

 mulating its recessive character or by the application of some 

 other pollen. 



Another principle : It is not possible to determine the number 

 of different forms under which the offspring of hybrids appear or 

 to arrange their forms with certainty, according to their genera-" 

 tions; but in the first generation bred from hybrids, the domi- 

 nant character reappears in the proportion of 3 to i ; the reces- 

 sive characters also reappear in the same numerical ratio, and 

 when fully formed they present no appreciable difference in their 

 subsequent development. 



When we attempt to trace the relationship of hybrids by a 

 small number of plants, the results are very uncertain, as the dif- 

 ferentiation of characters increase in cubic ratio. For instance: 

 if two different stocks differ in seven characters, and 100 and 200 

 plants are raised from the seeds of their hybrids to determine 

 the grade of relationship of the offspring, we can easily see how 

 uncertain the decision must become since for seven differentiating 

 characters the combination series contains 16,384 individuals, 

 under 2,187 various forms. Different relationships could assert 

 their predominance as chance presented this or that form to the 

 observer. In applying this law to the production of plums or of 

 apples we can plainly see where so much variation comes in. as it 

 would be rare to attempt to cross two varieties without more or 

 less differential characters in the pollen and egg cells. In 

 crossing two varieties of native plums it is immaterial which one 



