246 
Aspects of Ecology. 
Dr. Clements hardly seems to appreciate the great obstacles to 
their attainment, though he admits that “it is not to be expected 
that uniform methods will come into general use immediately.” 
In the matter of scale, for instance, Dr. Clements rightly insists 
on the desirability of a universal decimal scale, the different cate¬ 
gories being employed according to the size of the area mapped. 
The advantage of such a system is obvious, but the practical diffi¬ 
culties are immense. In countries, such as our own, where decimal 
units of measurement are not employed in topographical map¬ 
making, it is practically out of the question to prepare vegetation 
maps on a decimal scale, simply because the existing topographical 
maps have to be used as a basis. 
Then again, with regard to colour, Dr. Clements gives a 
universal colour scheme based on the colour standard of Saccardo’s 
Chromotaxia, and apparently intended to include all possible 
formations and their varieties. Such a scheme might be success¬ 
fully applied to small scale maps of the vegetation of considerable 
portions of the earth’s surface, such as a country as a whole, or in 
some cases to smaller areas. But in many instances in which it is 
desirable to have coloured vegetation maps, e.g., on scales between 
1:10,000 and 1:1,000, the number of “associations” or “consocies” 
(to use our author’s term) which it may be desired to show would 
make it impossible to use easily distinguishable tints, keeping 
within the limits of the prescribed formation colour. Undesirable 
and bewildering as the present confusion of colours undoubtedly is, 
there seems no escape from it till more experience has taught us 
exactly the types of vegetation unit which we want to map in 
colours—at least that is the present conclusion of phytocarto¬ 
graphers in this country. When that experience has been acquired it 
may be possible to arrive at a general agreement with regard to the 
colouring of maps within certain limits of scale, but it may fairly 
be doubted if enough easily distinguishable tints exist to make 
possible the application of a universal scheme to all coloured 
vegetation maps. If they do, so much the better. 
It is to be hoped that enough data to furnish the basis of an 
agreement may be available by 1910, the date of the next Inter¬ 
national Botanical Congress. This is certainly a question only to 
be settled by international agreement, and it seems premature to put 
forward a scheme with any hope of general acceptance. Meanwhile 
systems of symbols which can be reproduced in black and white 
may be employed, especially for the larger scale maps of small 
