210 Retrograde Varieties 



are inspected at the time of the fullest display 

 of the varietal characters, the obvious hybrids 

 will be eliminated, but the hidden ones will of ne- 

 cessity be spared, as they are concealed among 

 the species, by the similarity of their type. 

 Hence, the harvest of the variety may be ren- 

 dered pure or nearly so, while the harvest of 

 the species will retain the seeds of the hybrids. 

 Moreover it will contain seeds originated by the 

 spontaneous but numerous crosses of the true 

 plants with the sparsely intermingled hybrids. 



This brings us to the question, as to what will 

 be the visible consequences of the occurrence of 

 such invisible hybrids in the following gener- 

 ation. In opposition to the direct eifects just 

 described, we may call them indirect. To judge 

 of their influence, we must know how hybrid 

 seeds of the first generation behave. 



In one of our lectures we will deal with the 

 laws that show the numerical relations known 

 as the laws of Mendel. But for our present 

 purpose, these numerical relations are only of 

 subordinate importance. What interests us here 

 is the fact that hybrids of varieties do not re- 

 main constant in the next generation but usu- 

 >ally split, as it is called, remaining hybrid 

 only in part of their offspring, the other por- 

 tion returning to the parental types. This how- 

 ever, will show itself only in those individuals 



