120 VEGETATION OF THE PEAK DISTRICT [CH. 
grassland and calcareous grassland, should not be placed in the 
same plant formation; and the same conclusion is indicated by 
a study of their floristic composition and the related plant. 
associations. 
Gradmann (1909: 94) has maintained that a plant forma- 
tion can be defined floristically; and if this conclusion be 
accepted, it would seem to be indicated that the siliceous 
grassland and the calcareous pasture, although often possessing 
the same physiognomy and the same plant form, must be 
assigned to different plant formations. 
On bushy banks, where there is some shelter from the wind 
and where the soil is comparatively damp, many shrubs of the 
ash woods and of calcareous scrub occur; and these shrubs, in 
their turn, shelter several herbaceous species of the ash woods 
and scrub. Many of such communities, in fact, appear to be 
progressive associations which will finally become ash woods; 
and it is impossible to draw any hard-and-fast boundary line 
between woods, scrub, and grassland either of the siliceous or 
the calcareous soils of this district. The transitional associa- 
tions of these hill-slopes are strictly analogous with the tran- 
sitional associations occurring on the wet, acidic, peaty soils of 
the “ Hochmoors so abundantly scattered in the foothills on the 
Jura ridges, the Black Forest, and the Vosges. In contrast to 
the Hochmoors of the north German plain, there occurs here, 
as is well known, Pinus montana in great communities, but by 
no means everywhere: even on the moors where it flourishes, 
wide stretches are often quite free from it. If one now starts 
with the ordinary physiognomical division [of forests, scrub, 
grassland, etc.], it becomes necessary to split the natural and 
sharply defined plant community of the Hochmoor into at least 
three if not into four or five formations; and these must further 
be assigned to the most varied positions in the system. 
According as Pinus montana forms well-developed trees, or 
is the dwarfed form, or is absent altogether, the bit of the 
Hochmoor in question belongs to the forest formations, or to 
the scrub formations, or to the moss formation: where Ericaceae 
occur socially the same Hochmoor becomes a dwarf-shrub 
formation: where a turf of Carices, Eriophorum, or Scheuch- 
zeria predominate, we have a ‘meadow. And yet the floristic 
composition is almost exactly the same: the local conditions, 
