260 Retrograde Varieties 



ations so as to be able to compare them with 

 one another, but did not find any difference. 

 The most interesting point however, is the like- 

 ness between the first generation, which ob- 

 viously must combine in its internal structure 

 the units of both parents, and the second and 

 later generations which are only of a derivative 

 nature. Next to this stands the fact that in 

 each generation all individuals are alike. No 

 reversion to the parental forms either in the 

 whole type or in the single characteristics has 

 ever been observed, though the leaves of some 

 hundreds, and the spikes and flowers of some 

 150 individual plants have been carefully ex- 

 amined. No segregation or splitting up takes 

 place. 



Here we have a clear, undoubted and rela- 

 tively simple, case of a true and pure species- 

 hybrid. No occurrence of possible varietal 

 characteristics obscures the result, and in this 

 respect this hybrid stands out much more 

 clearly than all those between garden-plants, 

 where varietal marks nearly always play a most' 

 important part. 



From the breeder's point of view our hybrid 

 Oenothera would be a distinct gain, were it not 

 for the difficulty of its propagation. But to en- 

 large the range of the varieties this simple and 

 stable form would need to be treated anew, by 



