———eEeEEe 
eS Se Oe eS 
Iv] GRASSLAND ASSOCIATIONS 133 
RELATIONSHIPS OF THE PLANT ASSOCIATIONS OF THE 
SILICEOUS AND THE CALCAREOUS SOILS 
Precisely the same line of reasoning which decides one to 
place the oak and birch woods in the same plant formation as 
the scrub and the grassland of the siliceous soils decides one 
also to place the ash woods and the scrub and the grassland of 
the calcareous soils in another single formation. 
The parallel relationships of these formations and associa- 
tions, as developed on the southern Pennines, may be expressed 
diagrammatically in the following manner :— 
Plant Formation Plant Formation 
of the of the 
Siliceous Soils? Caleareous Soils! 
” 2 
8 Oak and Birch woods Ash woods S 
5 Die 5 
= Scrub cng OF Scrub E 
eS a | 3 3S 
g wilt 2 
2 Siliceous grassland Caleareous grassland 2 
1 Cf. Grisebach’s (1846: 73 and 156, and 1849 : 340—342) usage of the term 
‘plant formation,” and also Schimper’s (1903 : 161). 
