230 BRITISH PLANTS 



II. Herbaceous Associations. 



1 . Dry or moist soils : 



(a) Lowland and Sub-Alpine Pastures 



(p. 258). 



(b) Limestone-Pasture (p. 259). 



(c) Alpine Pasture (p. 259). 



2. Wet soils, with accumulation of organic 



matter : 

 Marsh (p. 244) and Reed-Swamp (p. 241). 



3. In water : 



Vegetation of Lakes, Streams, and Ditches 

 in the lowlands (p. 234). 



B. Associations with a Water-Supply Poor in Mineral 

 Food. 



I. Forest. 



Coniferous Woods. Soils poor, chiefly sand 

 and peat, liable to excessive moisture and 

 to drought (p. 273). 



II. Herbaceous Associations. 



1. Dry soils : 



Vegetation of Fixed Sand-dunes (p. 282). 



2. Moist soils more or less mixed with peaty 



humus : 



(a) Grass - Heath. Grassy turf, with 



heath-plants ; moisture variable, 

 water retained in soil by peat, but 

 periods of drought occur (p. 250). 



(b) Calluna-Heath. Soil poor, with mix- 



ture of peaty humus ; drainage 

 good, and moisture not well main- 

 tained, therefore liable to drought 

 (p. 252). 



3. Substratum of continuous peat ; moisture 



variable according to depth of peat and 



rate of drainage. 



(a) Heather-Moor. On sloping ground ; 

 soil poor and covered with a felted 

 layer of peat (p. 252). 



