68 
R. H. Yapp. 
far larger scale in the Norfolk Broads. 1 The general vegetation of 
Wicken Fen, however, affords an excellent example of some of the 
more advanced stages in the formation of dry land from marshes; 
and it is with this vegetation that the remainder of the present 
sketch will deal. 
The dominant herbaceous plants are Cladium Mariscus, Molinia 
coerulea and Phragmites communis, though J uncus obtusifiorus and 
several species of Cnrex are exceedingly abundant. But though 
here and there either Cladium or Molinia or even Phragmites may 
be locally dominant, almost to the exclusion of the other two, so 
that we might speak of “ Molinietum,” &c., associations; yet, for 
the most part, the vegetation presents a bewildering tangle of the 
most mixed character. The dominant species are present in almost 
every conceivable proportion, while intermingled with them are 
ever varying numbers of other constituents of the vegetation : so 
that a definite mapping of the different plant associations repre¬ 
sented here would be a difficult, if not an impossible task. To 
some extent this intermixture is probably due to the periodic 
harvesting of the vegetation. The latter is classified by the 
Fenmen into “ sedge ” and “litter.” The “sedge ” is the vegeta¬ 
tion where Cladium is dominant: this is harvested about once in 
four years, and is mainly used for thatching. “ Litter ” on the 
other hand is the name applied to the more mixed vegetation, 
which is cut about once in two years, and is used as litter, or even 
in some cases as fodder for farm stock. Now Cladium is a slow- 
growing evergreen plant, which will form, if left to itself under 
favourable conditions, very dense growths, often to the exclusion 
of other species. The periodic cutting almost undoubtedly leads to 
a greater admixture with it of more rapidly growing plants, while 
excessive cutting may even result in its local extermination. But 
other changes in the vegetation, which cannot be so readily 
attributed to the cutting, seem to have taken place in recent times. 
These will be dealt with later in this paper. 
Relations of the Plants to Soil Moisture. 
Wallis 3 gives two lists, which contain a few of the more 
important species found respectively in the dry and damp portions 
1 Stalham Broad for instance, close to which is situated Mr. 
Gurney’s Sutton Broad Laboratory, shows very finely many 
of the earlier stages in the formation of land from an open 
sheet of water, through the agency of swamp and marsh 
vegetation. 
2 Wallis, l.c., p. 220, 
