96 EXPERIMENTAL EVOLUTION LECT. 



Plantes qui naissent ou se renouvellent aux environs de 

 Paris} was able to show that the two so-called species 

 are one and the same. " Here is the proof," he says : 

 " When the same seed, sown in fertile and infertile soil, 

 yields the two so-called species, one must conclude 

 that there is but one single species, and that that which 

 seems to establish a difference between the two so- 

 called species, can only come from the climate and 

 culture. It is certain, as I have often witnessed the fact, 

 that the same seed, sown in fertile and infertile 

 soils, produces the two alleged species." And Prof. 

 Bonnier, recently, in his Etudes sur la Vegetation de la 

 Valle'e de Chamounix et de la Chaine du Mont-Blanc 

 (1889), says, corroborating others, that "in high alti- 

 tudes the appearance of the same species is dissimilar : 

 the stems straggle on the ground, leaves are narrower 

 and thicker, flowers are comparatively large and of 

 higher colour, and most of the plants even lose many 

 morphological characters which they possess in the 

 plains. . . . The characters of plants of high altitudes 

 are even different enough to have induced many 

 writers to describe these alpine forms as particular 

 species." Prof. Bonnier's statements are of especial 

 value from the fact that they are based on facts derived 

 from experiments made in stations situated at different 

 altitudes ; they are not facts of mere observation. 



1 1740, 6 vol. in 1 8, vol, iii. p. 244. 



