Chapter III 



—35— 



On Areas 



Sisymbrium 



In this case by all three methods we get the same result: the exist- 

 ence of two centers, one in the Mediterranean Basin and one in the 

 Andes. This connection between the Mediterranean Basin and Central 

 America and adjoining territories of North and South America is 

 characteristic of a number of genera, such as Draha, Eryngium, Cen- 

 taurea, Astragalus, Trifolium, Lupinus, etc. But such an exact agree- 

 ment of results from all three methods of investigation does not, by 

 any means, always hold true. As an illustration of this, we may take 

 the distribution of sections in the genus Carex, for each of its subgenera 

 separately, and compare the data thus obtained by Szymkiewicz with 

 those given above for species. 



Carex 



In this table there does not stand out any definite center of the area 

 of the genus, the East-Asiatic center so prominent in the other table 

 for the genus Carex not being in evidence here at all. We thus see how 



