1903] VEGETATION OF THE BAY OF FUNDY MARSHES 443 
usually occupied by flat bog (Ericetum), but on the dry marsh 
it is more likely to form a strip of swamp, with alders, black 
Spruce, and blue flag. This forms at least one association, 
probably more, but I have not attempted to study it, and it 
remains for future investigation. 
The succession of the plants of the marshland in space and in 
time. 
The succession of the plants of the marshland within associ- 
ations, both in space and in time, and of the associations within 
the formations, have been described in the preceding pages, 
but we may here summarize the subject and attempt to represent 
it graphically. Then we must consider the natural succession 
which takes place in the reclamation of the marshes. 
Fic. 15.— Diagram to show the distribution of the principal associations of the 
marsh land in relation to one another. e tops of the curves show the places of 
maximum development of the association, and the places where they overlap are the 
Places of competition. 4 is extreme high tide level, and 2 ordinary high tide. The 
“ditch” is not a drainage ditch but one of those from which mud has been taken for 
the dikes. 
The succession of the associations on the marshland is about 
as represented in fig. 75. The form given to each association is 
intended to represent its culmination at its optimum of size and 
vigor, and to show that the associations only mingle on their 
Margins when their optima are past. These relations may be 
brought out in another manner and correlated with the distribu- 
tion of the prepotent physical factors of water and salt, by 
means of the curves of fig. 16, which, however, it is to be 
remembered, are not constructed from actual measurements, but 
Only ideally from observation. They have their chief interest 
as a prediction of the way in which such facts will ultimately be 
represented. 
The distribution of the associations on the dikes is notable, 
