Ecology. 33 
and shrubs of our hedges and plantations, to constitute a mixed flora and 
fauna such as form the ground mass of many of our county lists. 
An index to the solution of these problems may be looked for in any 
considerable patch of woodland, where it will be found that the safest 
guide to virgin conditions is in a combined study of the plant and animal 
association. The virgin forest usually holds peculiar species not found in 
the surrounding districts, whereas plantations are, for the most part, free 
from such associations, but contain a number of otherwise plastic, but shade- 
loving, species which are widely scattered through the country. 
Some insects are now found wherever their food plant is established, 
and these can be shown in certain cases to be habitual migrants. Others 
are aliens by derivation, and not rarely of the nature of insect pests that 
particularly infest areas where crop-plants are closely grown in quantities 
for economic purposes. | 
4. EcoLoGy THE Proper METHOD FoR RECORDING DISTRIBUTION. 
How then can we extricate our plant and animal associations from this 
complex of confusion? We should cease from merely recording the presence 
of a certain species in this and that county. We must ascertain the head- 
quarters of a virgin flora and fauna and set ourselves to master the relations 
of the associations, looking, in the meantime, on those plants and animals 
that have adopted the new conditions as “weeds” and “ camp-followers,” 
only to be traced to their place of origin after the main framework of the 
original associations has been established. 
The faunal and floral relations of our moorland, heath and chalk grassland, 
should be acquired with the greater precision since they have been the 
least altered, and their associations cover the widest areas. Next in order 
would come the migratory formations most resistant to reclamation, as those 
of the blown sand and the reed-belt, salt marsh and aquatic habitats. In our 
forest formations we unfortunately can but hope to pick up the remnants 
of a vast bygone, while our fens are only too well known for the numbers 
of their extinct plants and animals. Many of the migratory formations, 
such as the grasslands, marshes, bushswamp and scrub, and especially the 
“camp-followers,” have to so marked a degree sent out their invading hordes 
into the great artificial complex, owing to the prevalence of fertile open 
formations and the rapid and extensive dispersal artificially provided, or 
have in themselves been so altered by drainage or other interference, that 
the task of solving their original relations is beset with great difficulty, but, 
as the other associations become better known, much can perhaps be done 
for them by the process of elimination. 
VOL, XIX. C 
