+ TYPES OF BRITISH PLANTS 
Now, the first necessity for the study of any subject 
is to decide on some arrangement or classification of the 
various individuals which it includes. You may say, 
“But why bother us with that; why not take up those 
that are specially interesting by themselves?” Well, 
let us take an example of what would be the result. 
Imagine trying to teach a school of two or three hundred 
boys without arranging them into forms. Of course it 
would be impossible, and so they are grouped into various 
divisions according to their knowledge. That is the great 
principle of their classification, and we want to find some 
principle which will serve us, in the same way, to group 
plants. Perhaps the most obvious difference at first sight 
is that of size. We might divide plants into trees, shrubs, 
herbs, and “planticule” (on the analogy of animalcule), 
but there are objections as obvious as there would be to 
arranging school forms on the same principle. For 
instance, the common groundsel, which we know here 
as a little wayside plant, has a first cousin in Eastern 
Africa which grows into a tree. The pufi-ball, which 
one meets in English fields, varying from the size of a 
marble to a small football, has a cousin in America which 
may be six feet in diameter, and one finds fossilised in 
coal mines gigantic mosses which once grew over England 
to the size of big trees. 
What, then, is the principle hic is adopted? Plants 
are put in a higher or lower “form” according to the 
extent to which they have adopted “division of labour,” 
that is according to the extent to which the various parts 
have become altered and “specialised” for various duties. 
In the lowest “form” we find plants consisting of one 
single cell or compartment, which performs all the various 
functions required, but in the highest class we find part of 
