244 
Aspects of Ecology. 
an indispensable part of the data necessary for the correlation of 
vegetation with the physical factors of the environment when, and 
if, the mechanism of this correlation reaches a practicable stage. 
It is obvious that a single quadrat presents a fair sample of a 
formation only when the formation is sensibly homogeneous. When 
this is not the the case it is necessary to locate several quadrats in 
different typical samples. 
The technique of quadrat charting cannot be entered into here, 1 
but it should be mentioned that a photograph is also taken of each 
quadrat by placing the camera at a suitable distance on a line drawn 
at right angles from the middle point of the front boundary of the 
quadrat, and tilting it forward so as to get a perspective view of the 
quadrat of greater depth than could be obtained if the camera were 
horizontal. Such a photograph supplements in an important way 
the information obtainable from the chart, since it shews the height 
and habit of the individual plants. In certain cases where the 
Vegetation is low and uniform a photograph of the quadrat taken 
from vertically above it, i.e., a photographic chart, is valuable, but 
in most cases it is impracticable. 
Just as the quadrat is used to record the structure of a homo¬ 
geneous formation, so the “transect” records the succession in 
space of zonally arranged vegetation. The transect is simply a 
section of the vegetation drawn across the direction of zonation. 
It is charted by recording to scale on a straight line the individual 
plants touching a tape laid down in the desired direction (line 
transect), or by recording in the same way as on a quadrat chart, 
the plants occurring on a belt of uniform breadth, i.e., between two 
parallel tapes (belt transect). 
A further method is necessary to record the height of the 
different plants, of special importance in the case of layered for¬ 
mations. This is done by means of the layer-chart corresponding 
to the line-transect, but on which the height of each plant touching 
the tape is recorded by a proportional vertical line. 
Any quadrat or transect on which it is desired to record 
changes in the vegetation can be made “permanent” by driving in 
labelled stakes at its corners and carefully locating the position so 
that it can be found again. 
Quadrats and transects can be “denuded” by removing their 
1 It is proposed soon to publish in this journal a detailed account 
of the quadrat and allied methods of recording the structure 
of vegetation, on behalf of the Central Committee for the 
Survey and Study of British Vegetation. 
