114 VEGETATION OF THE PEAK DISTRICT [CH. 
(2) Molinia Grassland 
The wetter type of siliceous grassland (cf. p. 106), dominated 
by the purple moor-grass (Molinia caerulea), is of far less extent 
in this district than the Nardus grassland, and much more local 
in its occurrence. 
The Molinia grassland occurs, as a rule, on flatter ground than 
the Nardus grassland (cf. figure 14). Ina very general way, the 
Molinia grassland affects the ground overlying the sandstone 
rocks and the Nardus grassland the steep slopes of the shales. 
Occasionally, the Molinia grassland occurs on shales where the 
drainage is obstructed by boulders which have fallen from an 
escarpment of sandstone. Invariably, the soil of the Molinia 
grassland is wet, often very wet, and more or less peaty. Such 
soil is, in this district, always acidic; but Molinia is by no 
means always confined to acidic soils. In East Anglia, for 
example, Molinia occurs on alkaline peaty soils; and here the 
associated species are different from those of acidic soils. On 
acidic soils, the Molinia grassland is transitional between grass- 
land and moorland, as was recognised by R. Smith (1900 b: 
454); and examples occur which might quite fairly be placed 
among the moorland associations. The moorland character is 
seen in its acidic peaty soil, often supersaturated with moisture, 
and in the abundance of associated species which characterize 
certain parts of the moorland. Some of the Molinia associa- 
tions of this district are almost demonstrably derived from 
oak or birch woods with a heathy ground flora; and there 
can be little doubt that it sometimes develops into moorland. 
Transitions of this nature occur on the south side of Longden- 
dale, near Crowden railway station. In a few cases, perhaps, 
Molinia invades the Nardus grassland ; and Molinia is frequently 
an associate in the heather moor. 
The plant (Molinia caerulea) has a wide range of form and 
habitat. The variety of form known as Molinia caerulea var. 
depauperata, with one-flowered spikelets and shorter leaves and 
shoots, occurs in very wet places. Usually, the plant (Molinia 
caerulea) is about half a metre high; but here and there a 
variety (M. caerulea var. major) with wide-spreading branches 
of the inflorescence occurs. The plant is deserving of a careful 
