270 MISS MARIETTA PALLIS ON THE 
rhizomes below and of 7ypha-rhizomes above (see Pl. 24, section II.). I 
believe, however, that Typha finally disappears and that the reed then 
resumes its interrupted course of growth: in the above case the reed 
probably remains “ giant” for a longer period of years, because—its 
normal output of branches having been inhibited—it is still in an early stage 
of branching when it resumes its full normal growth, i. e., it is morpho- 
logically still juvenile (see footnote on p. 267 and also p. 253). 
The 7'ypha-rhizome apparently has a short life compared with that of the 
reed ; the rhizome-layer of living Typha angustifolia, for instance, is rarely 
20 cm. (8 inches) thick, though the whole Typha-layer may be more than 
double that thickness. АП the lower portion consists of dead rhizomes and 
rootlets in different stages of decomposition and yields a reddish evil-smelling 
ooze. There is, in general, much more and presumably much earlier de- 
composition in a Typha- than in a reed-layer, hence also the ease with 
which a reed-swamp can be crossed on foot, as compared with a Typha-swamp. 
That the reed is merely inhibited for a time appears to be highly probable 
from the fact that in Norfolk, for example, there is no 7ypha-fen, though 
Typha occurs as a rare accompanying plant of fen, and yet is, as already 
explained, often the successful competitor in the beginning *. The youngest 
fens are nearly all Phragmites-fens, even where there is а 7ypha-swamp in 
the water immediately in front of them. 
The Succession on Plav and East Anglian Fen. 
The reed is, I think, succeeded either by another dominant, Cladium 
Mariscus, В. Br., or, if no plant present is able to take its place as a 
dominant, by а mixed assemblage of the plants which accompany it, giving 
rise to mixed-sedge-fen. 
In East Anglia, the succession following on the death of Phragmites 
greatly resembles the one on Plav. East Anglian reed-fen is followed by 
sedge-fen often with Cladium dominant, or by mixed-sedge-fen consisting 
chiefly of Carices amongst which Carew stricta, Good., and Carex riparia, 
Curtis, are usually the most abundant species (see Appendix D, p. 277). 
After the mixed-sedge-fen stage, the succession in Rumania and East Anglia 
differs markedly. In East Anglia, carr-, Juncus obtusiflorus-fen, or Molinia 
cœrulea-fen follow, and in Rumania salt-marsh plants appear as a direct 
result of the climate (see Appendix D, p. 279). 
Good examples of typical sedge-fen, with Cladium dominant, occur in 
many spots on Sutton-High-Fen, on the river Ant, and in Breydon-Horsey 
(see РІ. 22. fig. 2), both in the Norfolk Broads, and also in the well-known 
Wicken sedge-fen of Cambridgeshire. On Sutton-High-Fen, mixed-sedge- 
fen, Juncus obtusiflorus-, and Molinia-fen are also to be seen; the latter 
stages also oceur in Wicken fen. 
* Typha angustifolia, Linn., and Phragmites communis, Trin., both invade about the 
same depth of water in the Broads, 7. e., a maximum of 4 feet (about 1:22 m.). 
