234 Retrograde Varieties 



strengthened, not indeed to the restoration of 

 the tinge of the species, but at least so far as 

 to leave no doubt as to the identity of the visi- 

 ble color of the species and the latent or sub- 

 latent one of the variety. 



I made such an experiment with the peach- 

 leaved harebell or Campanula persicifolia. The 

 white variety of this species, which is often met 

 with in our gardens, shows a very pale bluish 

 hue when cultivated in large quantities, which 

 however is subject to individual variations. I 

 selected some plants with a decided tinge, 

 flowered them separately, sowed their seeds, 

 and repeated this during two generations. The 

 result was an increase of the color on the tips 

 of the segments of the corolla in a few in- 

 dividuals, most of them remaining as purely 

 white as the original strain. But in those few 

 plants the color was very manifest, individually 

 variable in degree, but always of the same blue 

 as in the species itself. 



Many other instances could be given. 

 Smooth varieties are seldom absolutely so, and 

 if scattering hairs are found on the leaves or 

 only on some more or less concealed parts, they 

 correspond in their character to those of the 

 species. So it is with prickles, and even the 

 thornless thorn-apple has fruits with surfaces 

 far from smooth. The thornless horse-chest- 



