PLANT ASSOCIATIONS 229 



and "Marsh Vegetation," by Professor Yapp, included 

 in the Bibliography, and numerous papers in the Journal 

 of Ecology, should be consulted. 



In a large district, where many associations exist, the 

 limits of each type should be recorded on a map, and 

 distinguished by some definite system of colouring, as 

 in the vegetation survey-maps of Smith, Moss, Lewis, 

 Pethybridge, and others. 



The following summary of the associations and groups 

 of associations to be dealt with is taken, with slight 

 modification, from W. G. Smith's Botanical Survey of 

 Scotland: III and IV, Forfar and Fife: — 



A. Associations with a Water-Supply comparatively 

 rich in Plant-Food. 



I. Forest. 



1. Dry or moist soils: 



(a) Oakwood - Associations. — On non- 

 peaty soils at low and moderate 

 elevations (p. 269). 



(6) Oak-Birch-Heath Association. — On 

 dry, coarse, sandy, and dry peaty 

 soils at low elevations (p. 271). 



(c) Birchwood- Association. — On non- 



calcareous soils at high elevations 

 (p. 271). 



(d) Ash-Oakwood Association. — On cal- 



careous clays, marls, impure lime- 

 stones, and calcareous sandstones 

 (p. 272). 



(e) Ash wood-Association. — On limestones 



(p. 272). 

 (/) Beechwood- Association. — On chalk 

 in the south-east of England and 

 on oolite in the Cotswold HUls 

 (P 272). 



2. Wet soils : 



Alder and Willow-Thickets (p. 243). 

 II. Herbaceous Associations. 

 1. Dry or moist soils : 



(a) Lowland and Sub-Alpine Pastures 

 (p. 258). 



