54 EXPERIMENTAL EVOLUTION LECT. 



mountains. Similarly Oxytropis montana and Trifo- 

 lium pratense are white in the Alps and Pyrenees, and 

 Geranium batrachoides, which is commonly bluish, 

 becomes variegated, and turns generally white when 

 it grows in unpropitious soil. There are white 

 varieties of many plants, such as Latnium purpureum 

 and Erica vulgaris, while Verbascum lycJinis, and 

 Campanula Trachelium bear flowers which are blue, 

 violet, or white, according to circumstances. 



Such instances might be given by hundreds, as is 

 well known. In some cases it would seem that the in- 

 fluence of environment is very plain, although difficult 

 to explain, for there are places where some natural 

 colours of plants or animals disappear soon, and are 

 replaced by lighter tints, or in many cases by white. 

 M. d'Apchier de Pruns records the fact as having been 

 noticed by himself on his own land, and it seems that 

 at Brassac les Mines, in central France, while oxen 

 become of lighter hue, and pheasants, pigeons, ducks, 

 &c., have more or less white feathers, plants with 

 variegated leaves soon become uniformly green. 1 And 

 some horticulturists and amateurs have complained, 

 similarly, of their garden or grounds, saying that they 

 find it impossible to keep variegated plants for 

 all return to the ordinary type. The causes of these 

 facts are difficult to ascertain, as the circumstances 

 1 Revue Horticole^ 1883, p. 316. 



