Fig. 20. A marsh meadow with its successor, a willow-alder association 
following the destroyed forest on better drained non peat covered sands of 
the Grasse River sand plain. 
Fig. 21. Typical beaver meadow (Calamagrostis canadensis and other 
grasses) occupying the flood plain of Grasse River adjacent to the bog. 
The absence of sphagnum and peat is noteworthy. The alder invasion is 
checked by mowing the meadow, but note greater abundance of it in mid- 
dle background. 
