THE PRINCIPLES OF PHYTOGEOGRAPHIC NOMEN- 
CLATURE.' 
PEHR OLSSON-SEFFER. 
THE confusion prevailing within the nomenclature of phyto- 
geography has of late been repeatedly brought up for discussion. 
A unanimous opinion exists as to the disadvantages resulting from 
the present chaotic terminology. Such a diversity of ideas prevails 
that every writer is obliged to explain in what sense he has used a 
technical term, and if he omits an explanation we are often left in 
doubt as to the interpretation of the expression used. An agreement 
has to be arrived at, sooner or later, and the sooner there is an end 
to the present disorder, the better for the progress of phytogeography 
and all concerned. 
This science is still in its infancy and very few of its doctrines are 
settled beyond doubt. We meet with contradictory views at every 
step. Sweeping generalizations, often based upon very imperfect 
observations, and described in vague and uncertain terms, full of 
ambiguities, threaten the development of this important science. 
Its advancement and success depend upon well-settled methods of 
investigation and description. The necessity of adopting a nomen- 
clature similar to that of other descriptive sciences is obvious. The 
prevalent fault of which we complain is not the absence of names 
and technical terms, but of the defective definition of the terms 
now in use. It has always been much easier to offer censure than 
to correct mistakes, easier to state evils than to relieve them. My 
object in this paper is not to give any proposals as to the detailed 
atrangement of phytogeographical nomenclature, but to discuss some 
of the general principles which ought to prevail in any attempt to 
revise the nomenclature so as to meet the present demands of the 
science. I have elsewhere, in papers appearing simultaneously 
with this, drawn attention to the terminology of certain phytogeo- 
graphical phenomena. 
Read before Section G of the American Association for the Advancement of 
Science, Philadelphia meeting, December 30, 1904. 
Igo5 179 
