3 28 PLANT-BREEDING 



have always borne the same marks, especially the same 

 deficiency of the pollen. This can be predicted with abso- 

 lute security from the single inspection of the first leaves 

 of the young seedlings. 



Here we have the full duplicate of so many cases of ob- 

 served correlations, with which we have previously dealt. 

 But in this case the repeated observation of the origin by a 

 single leap may be considered as a direct experimental proof 

 of what, in other cases, can be derived only from comparative 

 studies. In such a case no chance coincidence, no depen- 

 dency on similar outer conditions of life, and no other hypoth- 

 esis can adequately explain the facts. Only the assumption 

 that one unit-character may affect different organs of the plant 

 in different and apparently independent ways gives a suffi- 

 cient idea of their internal connection. 



The same correlations may be seen in most of my other 

 mutants. The scintillans and the oblonga are small types, 

 recognizable in their youth by their narrow leaves. The 

 albida is whitish and very delicate and has its peculiar shape 

 of spikes and flowers. The laevifolia combines smooth 

 leaves with a propensity for reducing the petals on the weaker 

 branches to an ovate form. But the most interesting instance 

 and the one which almost exactly corresponds to the corre- 

 lation between botanical and practically valuable characters 

 of the agricultural crops is that of the (Enothera gigas. Its 

 botanical marks are the dense foliage, the large flowers, the 

 swollen flower-buds, and the small, but thick pods with their 

 less numerous, but bigger seeds. Its cultural feature is its 

 great tendency to be biennial. The parent species and 

 most of its other derivatives can easily be cultivated as an- 

 nuals, and the rubrinervis evidently prefers this condition. 

 On the other hand, the gigas prefers to develop its stems only 

 in the second year. Under the conditions existing in my 

 experimental garden, it ordinarily defies all endeavors to 



