318 GEOGRAPHICAL BOTANY. 



and certain winter corn. In this more comprehensive 

 point of view, the separate denomination of the South of 

 Scandinavia as the district of the exclusive cultivation of 

 rye, and of Scotland as that of barley, disappears, as 

 circumstances not founded upon climatic conditions. 



2. Zone of rye and wheat. This is considered as 

 extending southwards to about the fiftieth degree of 

 latitude, or as far as the polar limits of the cultivation of 

 the vine. 



3. Zone of wheat. To this, those parts of Europe 

 and Western Asia belong which lie south of the fiftieth 

 degree. In several districts maize is cultivated as well as 

 wheat. 



4. Zone of rice and wheat in those provinces which 

 are subject to the influence of tropical seasons. In tro- 

 pical Western Africa rice and maize occupy the place of 

 the former. 



In America, where these relations are modified by the 

 greater extent to which maize is cultivated, Berghaus 

 distinguishes the following zones : rye, wheat, and barley 

 (i. e. summer Cerealia) ; rye and maize ; wheat and 

 maize ; wheat ; in the tropical zone maize is the principal 

 cereal grain. With these sketches the author has com- 

 bined indications of the distribution of other nutritive 

 plants, and has illustrated, in separate charts, the districts 

 in which the most important plants of commerce are 

 produced. The two following sheets contain the statistical 

 numerical proportions of the Flora of Europe, which, not 

 being susceptible of tabular arrangement, and being sub- 

 ject to very important differences in the views taken of 

 the definition of the species and botanical groups, were 

 not adapted, in the present state of botanical geography, 

 to graphic representation. Although the same applies 

 still more to the last sheet upon Germany, which appeared 

 in 1841, nevertheless the review of the polar and 

 equatorial limits of numerous woody and cultivated 

 plants in Europe, deserves great praise, inasmuch as the 

 observations made use of in it have appeared to us, 



