ig 2 
A. G. Tansley. 
the papers of some of its votaries; on the other hand the hostility 
alluded to is not seldom due to misapprehension, and it therefore 
appears useful to consider the subject from a general point of view in 
the hope of pointing out some of its dangers and of clearing up 
some of the misapprehension. 
In what follows the term “ Ecology ” is used in a somewhat nar¬ 
rower sense than is often the case. Instead of taking it as synonymous 
with “Bionomics” or “Natural History,” to include all the vital 
relations of plants, as living and competitive organisms, with their 
surroundings and with one another, it will be restricted to what may 
be called the topographical aspect of these relations, or, in other 
words, to those relations which depend directly upon differences 
of habitat among plants. In this sense it is practically equivalent 
to the subject matter of Warming’s book, a work that may be 
truly described by that often abused term “ epoch-making,” 
CEcologische PJJanzengeographie, or to that of Schimper’s encyclo¬ 
paedic work Pflanzengeographie auf physiologischen Grundlage. 
Though it may be open to question whether this use is strictly 
justifiable on logical or on etymological grounds, there can be no 
doubt that we want a single term for the subject matter so defined, 
as is sufficiently evidenced by the limitation of the subject matter 
of Schimper and Warming, and this is one which is simple and 
ready to hand. A single critical instance of the distinction to be 
drawn will make this limitation of subject matter perfectly clear. 
The study of individual pollination-mechanisms or of pollination- 
mechanisms in general would not be included as part of the subject- 
matter of ecology, since they do not directly depend upon any 
topographical factor ; but, on the other hand, the general result 
arrived at by Hermann Muller in his Alpcnbhuiien, that Alpine 
flowers are especially and pre-eminently adapted to pollination by 
Lepidoptera, as opposed to the bee- and fly-pollination prevalent 
in the lowlands, is an integral part of the ecology of Alpine 
plants, since a topographical factor clearly enters into this adap¬ 
tation, the interrelation of the flowers and insects of the Alps as 
a habitat exhibiting characteristic life-conditions shewing a 
specialisation of its own. 
As thus defined Ecology is simply the topographical physiology 
of plants, (or, as Schimper has it, Plant-Geography on a physio¬ 
logical basis)—using physiology in its wider sense to include all 
functional relations—and this is a fact which we shall do well to 
keep continually in mind. 
When we survey the vegetation of the globe, the first great 
