26 o 
FLORA OF THE SUNDRIBUNS. 
Existiiio’ Settlements.— In the extensive clearings that .occupy 
much of the eastern Sundribuns, and in the line of constantly encroach- 
ing settlements along the northern border of the swamp-forests, the 
proportion of species introduced by man, whether purposely or by 
accident, is naturally very much higher than on abandoned sites. 
Another class of species well represented in such localities is that of 
plants introduced in all probability by water-birds : this is to be 
explained by the existence of many still-water ditches behind the 
embankments that have been thrown up to keep out the high tides, and 
by the presence of small ponds dug to provide drinking-water for the 
population. The number of species introduced by fruit-eating birds, 
on the other hand, is much smaller ; this doubtless is to be explained by 
the absence of trees on which to rest, and the presence of inhabitants, 
rendering these clearings less inviting as resting places for birds of this 
,kind than are the forests in their vicinity. Of the inanimate agencies, 
wind has been here the least effective ; rivers, as might be expected, 
have been responsible for the introduction of not a few species that 
find the conditions in these clearings practically identical with those 
in the Bengal rice-plain whence they have been brought, and that 
therefore survive here when in the swamp -forests or at the sea-face 
they can find no foothold. Contrary to expectation, however, it is found 
that the agency of the sea is responsible for a very marked proportion. 
of the species present in these clearings. This is to a considerable 
extent due to the survival of swamp-forest species along the banks of 
khals and on the sides of bunds, and to some extent owing to the fact 
that these clearings offer conditions suitable for plants growing at the 
sea-face that are incapable of subsisting in the swamp-forests. The 
littoral element in the vegetation of these clearings is not, however, to 
be explained entirely in this way ; there are a number of species, very 
charactetistic of sea-shores elsewhere in South-Eastern Asia, which one 
does not find in the Bengal plain outside the limits of these Sundri- 
bun clearings, but which one looks for equally in vain in the swamp- 
forests or at the sea-face. 
Maritime species of this class are Phaseolus adenanthus^ very 
plentiful on Andaman beaches; Stictocardia tiliasfolia, Agyneia 
baccif-Qrmis, Blumea amplectens var. maritimay Sphwranthus 
africanuSy Wedelia scandensy Pluchea indica2inA Suaeda maritima-— 
both occasionally met with in naturally clear spaces in the forests, 
Azimay Psilotrichumy Solatium trilohatumy Cyperus scartosus, 
Fimbristylis polytrichotdes var. halophila^ Paspalum distichum, 
Scirpus triqueter var. segregata, . Other sea-borne species in open 
clearings are Pycreus polystachyus and Zoysia. Species introduced 
by the sea that survive along bunds and banks of khals in the clearings 
