392 Flahault : Phytogeographic Nomenclature 



region of the steppes, region of coniferous forests, etc. This idea 

 of botanic region, so diversely interpreted, designates geographic 

 units of a superior class, or it is not subordinated to others 

 according to the meaning given it, so that the names of regions, 

 provinces, zones, districts, sectors, etc., designate very different 

 things according to the authors who use them. 



A. Engler * has adopted a series of names for phytogeographic 

 units of different classes ; but he has not been followed by 

 the majority of botanists, notwithstanding the authority of his 

 writings, as possibly this series does not meet with the require- 

 ments of a science which demands more and more precision. 

 Without any doubt, in 1879, Engler did not pretend to regu- 

 late a question of method, not wishing to establish a code of 

 phytogeographic nomenclature, ne varietur. He intended, it 

 seems to me, only to express clearly the facts which are the 

 object of his memoir ; he has chosen the terms that he employs, 

 simply because they appear the most convenient to him, without 

 discussing all their advantages or inconveniences. 



The time has come when it appears necessary that a technical 

 terminology should be established or we shall no longer under- 

 stand each other. A comparison of facts will be facilitated if we 

 adopt a common basis and a sufficient uniformity of expression. 

 We will be enabled to compare comparable units if we restrict 



1 



the same name for units of the same value. We will be able under 

 these conditions to speak of the temperate regions with or with- 

 out a dry season ; we will be able to draw a parallel between 

 the Mediterranean, Australian, Cape, Californian and Chilian 

 regions, the desert domains of northern Africa, of western and 

 central Asia, of Australia, of Colorado and Mexico, the district of 

 the Vosges and of the Maures, the subalpine and alpine zones of 

 the Alps, the Pyrenees and the Caucasus, etc. Dr. O. Warburg, 

 at the geographic congress of Berlin insisted on the necessity of 

 such an understanding as soon as possible. 



This article does not pretend to solve the problem ; but if the 

 time has come for a statement, the Botanical Congress furnishes an 

 opportunity which must not be allowed to pass. It does not appear 

 useless, at all events, to propose some principles and to advance 



* A. Engler, Versuch einer Entwicklungsgesch. der extratrop. Florengebiete 



