170 VEGETATION OF THE PEAK DISTRICT [cH. 
Tansley (1911: 208) has recently discussed the conditions 
of British moors and fens; and in his Types of British Vege- 
tation, accounts are given of the vegetation of the two plant 
formations. The “fenland formation” of Caithness, recently 
described by Crampton (1911: 74), is certainly not true fen, 
but a type of vegetation intermediate between fen and moor, 
and termed Uebergangsmoor (transitional moor) by Weber 
(1908: 95). 
Moors AND FENS 
The only test of fen peat and moor peat, which is here 
regarded as really fundamental, is that depending on the 
amount of soluble mineral matter in: the peat; and as this 
is very low in the case of all the local peats examined, there 
is no difficulty in referring all the plant associations developed 
on peat in this district to the moor formation as opposed 
to the fen formation. 
The following characteristics distinguish the two forma- 
tions :— 
1, Fen peat is rich, moor peat is poor in soluble mineral 
matter. 
2. Fen waters are alkaline, moor waters acid in reaction. 
3. Fen peat often, moor peat rarely, contains the remains 
of molluscan shells. 
4, The following plants are locally subdominant or very 
abundant on the peaty fens of eastern England :— 
Cladium Mariscus Calamagrostis lanceolata 
Schoenus nigricans Molinia caerulea 
Phragmites communis Juncus obtusiflorus 
Of these species, only one—Molinia caerulea—occurs on the 
moors of the Peak District. 
The following species are locally dominant or very abundant 
on British moors :— 
Sphagnum spp. Vaccinium Myrtillus 
Polytrichum commune V. Vitis-idaea 
Rhacomitrium lanuginosum Scirpus caespitosus 
Empetrum nigrum Eriophorum vaginatum 
Rubus Chamaemorus E. angustifolium 
Erica cinerea Carex Goodenowii 
E. Tetralix Molinia caerulea 
Calluna vulgaris Juncus squarrosus 
