ently points to the agency of man in distributing these 
plants, as it is the only condition wanting. 
The nomenclature here adopted is that of the London 
Catalogue of British Plants of 1867, printed by Robert 
Hardwicke. 
In our remarks we have considered the whole four plots as 
if they were one observed at different periods ; but it is 
obvious that this is not absolutely correct, but that subse- 
quent investigations will be required to confirm our con- 
clusions. 
Mr. J. Sidebotham wrote, stating that Polygonum con- 
volvulus was the only plant which grew from soil obtained 
from under the foundations of a wall built some thirty 
years ago at Bowdon. 
