398 Flahault: Phytogeographic Nomenclature 



may be recognized of distinguishing two subdistricts in the district 

 of the Maures and that of the Esterel, if with the mineralogic 

 differences between the ancient and modern eruptive soils are cor- 

 responding botanic differences, which have escaped us as yet. 



Prof. Briquet has distinguished several subdistricts in the western 

 Alps and in the Jura.* In France for the same causes, and prob- 

 ably in all countries of ancient civilization where the soil has re- 

 tained the impress of history, botanic districts often coincide ac- 

 curately with the ancient "country." In mountain groups the 

 subdivisions recognized by the inhabitants also represent the 

 natural divisions of districts. The names of countries and of 

 mountain groups which are used by the population may often be 

 given to indicate districts or subdistricts without resulting error 

 or ambiguity. 



The last term remains to be spoken of, that of station, the final 



one of the series of geographic and topographic units. 



In 1844, Wimmerf insisted on the necessity of adding to the 

 morphological diagnosis of each species a phytogeographic de- 

 scription u which will determine with precision and in definite 

 terms all environmental conditions ; for a description of this kind 

 contributes not less than the first to a knowledge of the species." 



A station is a circumscription of any extent, but oftener limited, 

 and represents a complete and definite ensemble of conditions of ex- 

 istence. Station sums up all that is necessary to the species which 

 occupy it, the combination of climatic and geographic factors 

 with the edaphic and biologic factors, that is to say the relation of 

 each species to the soil and to associated species. 



The disappearance or only the modification of an element, a 

 specialization or even a very slight variation of any factor would 

 be sufficient to determine a difference of station. The vocabulary 

 of each country, born of the environment and need that puts a peo- 

 ple to the test of expressing facts and phenomena which they 

 observe each day, should furnish the means of designating stations 

 peculiar to the country. The Scotch heaths, the Russian steppes, 

 the moors of Brittany, the prairies of North America, the " pres- 

 bois " of our Alps, represent peculiar forms of vegetation which 



* John Briquet, Rech. sur la flore du district Savoisien, 1890. 

 f Wimmer, Flora der Schlesien, 1844. 



