56 TRANSACTIONS OF THE [Sess. Lxxrv. 
published memoir. The actual field observations are re- 
corded on the Ordnance Survey maps of the scale “one 
inch to one mile,” but in many cases the authors prefer to 
use the larger scale of “six inches to one mile,” and this is 
certainly the better plan. The usual practice is to colour 
all the existing types of vegetation covering a sufficiently 
large area, giving the principal plant communities a dis- 
tinguishing colour and letter, and indicating mixed com- 
munities by blending colours and symbols. In naming 
these plant communities, the names of distinctive plant 
species are used, ¢.g. oak wood, heather moor, ete. 
(c) Investigations on the influence of climatic, topo- 
graphic, edaphic, and biological factors and their influence 
on the distribution of the various plant communities.—In 
the earlier primary surveys this side of the research was 
generally rather superficial, because large areas were dealt 
with, and obviously the necessary observations for such 
investigations can only be successfully carried out over 
small areas. It is noteworthy, however, that each suc- 
cessive memoir devotes more space to the investigations 
on environment, and just at present there is great activity 
in this direction which will make itself felt in future 
contributions.} 
(d) Examination of analysis from a synthetic stand- 
povnt.—This involves deductions from the observations of 
the conditions which determine plant-distribution and of 
the origin and status of the plant communities. 
The present position of this aspect of botanical survey 
in Britain may now be briefly reviewed. Most of the 
work attempted has been “primary survey” or recon- 
naissances over fairly large areas with the view of ascer- 
taining the outstanding types of vegetation (see list at end). 
The result is a series of memoirs with maps relating to 
districts in England, Scotland, and Ireland. The advan- 
tages of the primary survey are generally admitted: it is 
the best preventive of narrow views, and an essential 
1 The following papers deal more particularly with the environ- 
mental conditions of small areas :—(a) T. W. Woodhead, “ Ecology of 
Woodland Plants in the Neighbourhood of Huddersfield” (Jour. Linn. 
Soc. Bot., vol. xxxvil., p. 333, 1906). (b) R. H. Yapp, “Stratification in 
the Vegetation of a Marsh, and its relations to Evaporation and Tem- 
perature” (Annals of Botany, xxiii., April 1909). 
