Fundamental Units of Vegetation. 
41 
Methods of Denoting Associations and Formations. 
Whilst Schouw’s plan (1822, 1823: 165) of referring to an 
an association by the suffiix -etuiu is simple and brief, it has its im¬ 
perfections. In the first place, it does not distinguish the species of 
the dominant plant, but only the genus to which the species 
belongs. The plan is particularly ambiguous in the case of such 
genera as Juncus, Ouercus, and Pinus, each of which contains 
several species which are dominant in unrelated associations. 
Cajander (1903 : 23) has a modification of Schouw’s plan, which, 
to a large extent, overcomes this difficulty ; and Cajander’s plan 
appears to meet with Warming’s approval (1909: 145). By this 
method, an association of jfuncus effusus is not referred to merely 
as a Juncetum, a term which might refer to an association of 
glaucus, or of jf. maritiinus, or of f. obtusiflonis, or of ff. squarrosus, 
and so on : Cajander’s plan is to add as a genitive the specific name 
of the dominant plant of the association. Thus an association of 
jf. effusus would be a Juncetum Junci effusi, or more briefly, a 
Juncetum effusi; and similarly an association of jf. maritimus 
would be a Juncetum maritimi. 
A second objection applies equally to Schouw’s plan and to 
Cajander’s modification of it. Neither method is applicable to 
mixed associations, which have no single dominant species. Of 
course, some characteristic species might, in certain cases, be 
utilized ; but this would be arbitrary and unscientific, and in some 
cases, perhaps, impracticable. 
The designation of a pure association by its dominant species 
is a very different matter from determining the association by such 
a species. Against the latter superficial method of determining 
associations Drude has expressed himself on several occasions; and 
recently Gradmann has emphatically condemned such a procedure. 
The naming of a pure association, however, by its dominant species 
is comparable with the plan of naming a systematic group after an 
easily recognizable character; and in neither case does such a 
name exhaust the characters of the group it denotes. 
With regard to denoting particular formations, Clements’ plan 
(1902 : 16 ; 1905 : 299) is comparable with the one propounded by 
Schouw for denoting associations. Clements has put forward a 
number of terms, each with the termination -ium } to denote various 
classes of formations (1902: 5). As this suffix would easily lead to 
