Table 8-4. (Concluded) 



Bog 



Marsh 



Chemical Conditions 



Predominance of strongly acid react- 

 ion. Percentage of saturation low. 

 Large quantity of colloids in 

 suspension. 



Potassium and nitrogen deficient in 

 soil (some nitrogen-fixing 

 bacteria present) . 



Percentage 



Acid or alkaline reaction 

 of oxygen saturation high. 

 Small quantity of colloids in 

 suspension. 



Potassium and nitrogen sufficient. 



Vegetation 



Presence (at some time) of a 

 floating mat usually dominated by 

 ericoid plants. 



Mat, when present, composed of 

 graminoid plants. 



Physiognomic dominance of curvi- 

 linear contours: much-branched 

 shrubs, cushionlike tufts of herbs 

 and mosses, curved surface 

 of raised bogs. 



Physiognomic dominance of recti- 

 linear contours: graminoid herbs, 

 flat surface of soil. 



On the whole, a bog is a large 

 cushion. 



Dominance of the ericaceous type in 

 many of the pioneer stages. 



Dominance of needle-leaved 

 types in the subclimax stages. 



Vegetal cover continuous, uneven, 

 forming cushions, eventually 

 parklike. 



Mosses (mostly Sphagnum ) always 

 forming the lowest layer. 



On the whole, a swamp is a wet 

 prarie . 



Dominance of the graminoid type in 

 the pioneer stages. 



Dominance of broad-leaved 

 types in the subclimax stages. 



Vegetal cover discontinuous, in 

 tufts or isolated individuals, 

 eventually thicketlike. 



Mosses (at least Sphagnum ) generally 

 absent. 



Fauna 



Animal life scarce, both in numbers 

 of species and of individuals. 



Animal life abundant. Both in 

 species and individuals. 



8-13 



10-80 



