GEOGRAPHICAL BOTANY. 



LN the first volume of the ' Physical Atlas' of Berghaus, 

 which is now completed, six sheets are devoted to graphic 

 representations in the department of Botanical Geography. 

 The first sheet, entitled ' Outlines/ forms a sequel to the 

 works of Humboldt and Schouw, and refers principally 

 to the geographic subdivision of vegetable formations ; in 

 the vertical direction it illustrates the serial gradations 

 of the regions, whilst in the horizontal direction it shows 

 the areal boundaries of the natural Floras. This repre- 

 sentation, however, appeared as early as 1838, and on 

 future revision would require considerable improvements. 

 The second sheet, which treats of the Districts in which 

 the most important products of culture are distributed, is 

 of greater interest. Its design consists in an attempt to 

 subdivide the province of agriculture throughout the en- 

 tire inhabited surface of the earth, according to the kinds 

 of Cerealia which predominate, whence general relations 

 are found between the climate and the productive power 

 of different countries. In the Old World the author dis- 

 tinguishes the following zones between the polar limits to 

 agriculture and the equator. 



1. Zone of barley and rye. It might with propriety 

 be called the zone of the summer Cerealia, inasmuch as 

 the duration of the winter is the most important condi- 

 tion which prevents the culture of the more productive 



