37 
Flora of the Ceylon Littoral. 
Fig. 12. An island in the Bentotta river entirely occupied by Mangrove 
vegetation. A belt of Acanthus two or three feet high occupies the 
water’s edge; behind in the centre is a tree of Sonneratia acida ; on 
each side bushes, of Brnguiera and some Chrysodium. 
(From a sketch). 
constituent of the vegetation, and Schimper has already sufficiently 
described the important part it plays at Negombo, some of the 
smaller islands in the lagoon consisting practically of this plant 
only. On the other hand this is not invariably the case, for at 
Balapitiya Acanthus is only very slightly represented, whilst the 
' rest of the mangrove vegetation is very well developed. This plant 
was also not met with at Ambalangodda. In other places, again, 
Acanthus is almost the sole representative of the typical mangrove- 
vegetation for considerable stretches along the estuaries (e.g. 
Kalutara, Bentotta). These very definite features in the distribution 
of this plant indicate that there are certain external factors, which 
will probably not be difficult to ascertain, determining its presence 
or absence at any locality. It is interesting to notice that it has 
stilt-roots somewhat like those of Rhizophora, though of course on 
a much smaller scale (Fig. 13). Sometimes it forms a thick under¬ 
growth in a mangrove wood on soil not covered by the tide at high 
water. 
Ceriops Candolleana is a member of the Rhizophoracese and 
resembles Rhizophora in its viviparous embryos, which reach a 
length of several inches before dropping from the tree. They are, 
however, both shorter and slenderer than those of Rhizophora. 
Some uncertainty seems to exist as to the root-system of Ceriops; 
Schimper enumerates it amongst the plants with pneumatophores, 
whilst Trimen describes stilt-roots as occurring in Ceriops, and this 
receives some confirmation from a figure (Fig. 19) in Schmidt’s 
paper. Karsten, 1 however, does not refer to either type, 
i Bibl Bot. Heft. 22, 1891, p. 49. 
