184 BOTANICAL GAZETTE [MARCH 
term zone in plant-geography, therefore, should signify the successive 
stages of vegetation from the base to the summit of a mountain, and 
nothing else. It is true that WAHLENBERG4 in 1812 designated these 
belts with the term regio, and if we followed the rule of absolute 
priority, this would be the correct term. Regio, however, was used 
long before WAHLENBERG’s time by botanical writers in the general 
sense of a geographical area of more or less definite extension, and 
so was zone. In this case we are confronted with two synonymous 
terms, and the only principle on which a decision can be based seems 
to be that of general usage. It must be admitted that it is an 
extremely difficult matter to lay down any rules that would take us 
out of dilemmas such as this. If it were possible to canvass the 
various authors to ascertain which term has been used more than 
the other to designate this special feature of mountain belts we are 
considering, it is very doubtful at what result we would arrive. 
Region, however, since Martius used it in 1831 for a certain phyto- 
geographical area, has generally been understood and adopted by 
the best writers for that purpose. FLAwAuLT has made the relation 
and usage of these two terms, zone and region, clear by adopting 
them in the sense advocated above. If that is universally done, we 
have to find other appropriate terms for the various conceptions 
that often have been called zones. Nor need we take refuge to the 
method of making new terms in this case, for we only have to make 
a selection from the multitude of expressions already used, and in 
selecting we can make a choice that will serve in other languages 
as well as our own, and thus to some extent satisfy the call for an 
international nomenclature. 
The first and most essential principle of nomenclature is clearness. 
To obtain this result, all the expressions used in technical terminology, 
whether they be old established names or newly coined ones, must 
be definite, concise, perfectly distinctive, and easily intelligible. 
All names and terms are for the sake of convenience. In order 
to insure mutual intelligibility, greater precision, and clearness, 
is imperative to avoid names that will create error or ambigully- 
It is not inconceivable that the need of short compendious namé 
and terms to denote phytogeographical facts or processes can be met 
4 Flora Lapponica. Berlin. 1812. 
