the Vegetation of a Country. 



443 



cording to the Flora of M. Guepin, the departments of the 

 centre of France according to the Flora of M. Boreau, and the 

 whole of France according to the Botanicon of M. Duby. The 

 cultivated species are excluded throughout*. 



It will be seen from this how incorrect it would be to make a 

 comparison between the proportions of the families in a depart- 

 ment of France and in a country of the size of Germany, and still 

 more in an immense region such as the United States or New 

 Holland. 



By ascertaining the proportions of the Compositre, Gramineae 

 or Leguminosre as compared with the Phanerogamia in all the 

 departments of France successively, and taking the averages, we 

 should not obtain the same proportions that would be found 

 from the Flora of the whole of France ; and the error would be 

 sometimes in one direction, sometimes in the other, according 

 to the relative specific areas of the three families. 



The following is another example, taken from Alsace and 

 Germany. I shall compare, 1. the Flora of Strasburg by 

 Kirschleger; 2. that of Baden, Alsace, Rhenish Bavaria, and 

 SchafFhausen by Grisselich; and, 3. that of Germany, including 

 Istria and Switzerland, according to Koch, deducting the cul- 

 tivated species. 



The variations are the same as in the preceding case ; that is 



* To avoid a departure from custom, in a circumstance where it was a 

 matter of indifference, I have allowed the weeds of cultivated lands to 

 remain, although they are not, properly speaking, spontaneous, and still 

 less aboriginal species. 



29* 



