396 Flahault : Phytogeographic Nomenclature 



make up the whole, projected, as it were, on the general surface 

 of the globe, in diversifying biologic conditions and in multiply- 

 ing phytogeographic problems. 



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The great fundamental zones are subdivided then into vegetative 

 regions which constitute the most important phytogeographic 

 units. The idea of zones in general answers the need of synthesis 

 and results from a consecutive comparison. The polar tundras 

 appear to us a region contiguous to the forest region of northern 

 Europe before we consider whether each of them should not be 

 classed in a different superior group. 



It being so, and because it appears necessary to reserve the 

 name of zone to express parallel belts following which the moun- 

 tain vegetation is divided, it seems advantageous to give the name 

 of Groups of Regions to the fundamental zones. 



So we would have a group of cold regions, one of temperate 

 and another of warm regions ; the same could be said of groups of 

 boreal, austral and tropical regions. 



It has been said that this primary grouping has for its prin- 

 cipal purpose the facilitating of a grouping of the second order ; it 

 is, therefore, arbitrary ; it suffices to make it good that it depends 

 on evident and incontestable facts. 



Botanic regions may be subdivided into secondary circum- 

 scriptions of variable extent in the determination of which the 

 variations of climate are also secondary, but which depend ordi- 

 narily on topographic and geographic conditions. 



Thus in the forest region of western Europe, the Atlantic 

 Coast countries are clearly distinguished from the lowlands border- 

 ing on the North Sea and from the valleys of the Rhine and Dan- 

 ube. The Mediterranean region south of the Pyrenees has not 

 the same character as in France or in northern Africa. 



To these subdivisions of regions Prof. Engler has given the 

 name province ; in many countries this word has an administra- 

 tive or political sense so that its use would give rise to ambigui- 

 ties. The word Domain seems more appropriate. 



In the forest region of western Europe there is distinguished 

 then an Atlantic domain, a domain of the plains of northern conti- 

 nental Europe and one of central Europe ; in the Mediterranean re- 

 gion there are the Iberian, the Mauritanian, French domains, etc. 



