152 VEGETATION OF THE PEAK DISTRICT [cu. 
SwAMpes (OR MARSHES) ON THE LIMESTONE 
Swamps are much less numerous in the limestone tract 
than on the less porous sandstones and shales. Most of the 
swamps in the limestone area occur at the bottoms of the 
dales, although a few occur on the grassy slopes, wherever 
springs issue through the soil. A very large number of species 
which characterize the swamps of the sandstone and shale are 
absent from those of the limestone, whilst some species are 
restricted to the limestone swamps. The following species 
have been found in the limestone swamps of north Derbyshire ; 
and it will be seen that the total floristic composition of the 
limestone swamps is very different from that of the sandstone 
swamps, just as the soluble mineral content of each is very 
different. These differences are sufficiently important to justify 
the placing of the two kinds of swamps in separate plant 
formations. 
Thalictrum flavum Yr si) Vi. dioies: la 
Trollius europaeus la Eupatorium cannabinum la 
Caltha palustris a Petasites ovatus la 
Chrysosplenium oppositi- Cnicus heterophyllus a 
folium | la C. palustris a 
C. alternifolium | la Festuca elatior r 
Parnassia palustris la F. arundinacea vr 
Spiraea Ulmaria a Scirpus compressus 
Potentilla erecta Oo (Blymus compressus) r 
Geum rivale la || Carex disticha l 
G. rivale x urbanum C. acuta r 
(=G. intermedium) la C. flacca ) 
Epilobium hirsutum a C. pendula ] 
Polemonium caeruleum la C. strigosa r 
Myosotis palustris la C. sylvatica ] 
Mentha spp. a Juncus glaucus la 
“M. rotundifolia” r J. compressus vr 
Pedicularis palustris r Helleborine palustris vr 
Valeriana officinalis Orchis maculata o toa 
(=V. Mikanii) la 
In similar limestone swamps of the mid-Pennines, the bird’s 
eye primrose (Primula farinosa) is abundant, and there reaches 
its southern British limit. 
Admitting that the two kinds of swamps should be placed 
in separate plant formations, the question arises as to which 
