44 
Tansley ami Frit sell. 
The fertile pinnae have the whole of their under surfaces covered 
with sporangia, giving the pinna a dark brown colour. 
Chrysodium is an extremely abundant plant in the brackish 
marshes, and on the banks of the tidal rivers and often gives a 
character of its own to the vegetation. On the whole it distinctly 
increases in amount as one gets further from the sea, and in this 
respect may be placed, as Schimper places it, beside Nipa, but in 
Ceylon it is much commoner than the latter, and is found high up 
the rivers where the water is scarcely salt, in association with tall 
freshwater riverside herbaceous plants, such as Susuin anthel- 
minticum, Phragmites Karka (Roxburghii), several species of 
Cyperns, e.g. C. dilutus, and Colocasia Antiquorum. Chrysodium is 
Fig. 15. View of a brackish lagoon south of Matara with narrow belt of 
mangroves ( Rhizopliora , etc.) fringing the shore from which the low 
hills rise steeply. (After a sketch by Dr. W. H. Lang). 
one of the cosmopolitan tropical “ semi-halophytes.” It is 
extremely abundant in the Malay region, covering immense tracts 
by the sides of the tidal rivers further from the sea than most of 
the true mangroves go, but often associated with Nipa and 
Sonneratia , and it is apparently equally common in America. 
We had no opportunity of making a study of the junction of 
either mangrove or semi-mangrove vegetation with typical land- 
vegetation, but it may help the reader to form a more definite 
picture if we describe the succession of forms seen in passing up 
some typical tidal rivers on the Ceylon coast. The vegetation of 
the estuarine mouths of all these rivers tends to be spoiled by 
clearing, embanking, and planting of coconuts. 
