4 8 
Tansley and Fritsch. 
the intermingling of Schimper’s Mangrove, Nipa-, and Barringtonia- 
formations and of inland forms. It recalls the river at Matara in 
the scanty development of Rhizophoraceae, but the banks of the 
Kalu Ganga are thickly wooded and the scarcity of the mangroves 
seems more the result of natural causes here than at Matara. At 
many points the banks slope more rapidly out of the water than in 
the two preceding cases and this may be the cause of the great 
scarcity of the typical genera. Near the mouth of the river 
a short stretch of fairly characteristic mangrove ( Rhizophora , 
Bruguiera, Acanthus, Sonnemtia, Cerhcra Odollam) is to be found on 
the north bank on either side of the railway bridge with occasional 
specimens of Nipa fruticans ; Dolicliandrone Rhecdii is also very 
characteristic of this region, hut becomes more abundant as we 
pass away from the mouth. Heritiem littomlis, and Clerodendron 
inerme were also occasionally observed on this part of the banks. 
On the other hand the island in mid-stream, which is joined to 
either bank by the railway bridge, bears no Rhizophoraceous 
species at all, Sonnemtia acida and Cerhera Odollam forming the 
main part of the woody vegetation. Barringtonia occurs at a few 
points on this island. As one moves up stream away from the 
railway bridge a number of new plants slowiy make their 
appearance (Cynometra raniiflora, Ardisia humilis, Eugenia caryo- 
phyllea, Ixora coccinea, Hippocratea obtusifolia), whilst the mangrove- 
element disappears more and more, giving way to Nipa fruticans, 
Barringtonia, etc., and occasional patches of Pandanus. Climbing 
plants also become commoner as we recede from the sea ; a species 
of Connarus is noticeable first, whilst subsequently Flagellaria indica 
and Caesalpinia Nuga become prominent features of the vegetation. 
In front of the shrubby and woody vegetation on the actual banks, 
one finds, as in all the Ceylon estuaries we visited, a very 
characteristic growth of marsh plants, rising up out of the water. 
On the island mentioned above this foreground is constituted by 
Susum anthelminthicum and a species of Cyperns, the one generally 
replacing the other. The same two plants also form a fringe on 
the banks of the river together with other species of Cy perns, and as 
we go up stream Phragmites Karka partly replaces them and with 
its long runners forms a conspicuous feature of the vegetation. 
Still further inland Chrysoditim aureum is very common down by 
the water’s edge and together with Nipa and Susum presents a very 
characteristic appearance. In front of these a submerged species 
of Aponogeton, A. crispum, and diverse floating plants ( Nytnphaea, 
