FLORA OF THE SUNDRIBUNS. 
257 
or by wind. None of the savannah species are likely to have been 
introduced by fruit-eating birds or by man and, on the whole, the 
inanimate agencies of dispersal,*— winds, river-currents or tides — are 
the probable agencies for all. 
Sea-Face.— The species that constitute the fence of shrubs and 
creepers immediately behind the line of low sand-hills that occur 
along the coast wherever the actual shore is subject to the influ- 
ence of the waves, and the species that are to be met with on 
these sand-hills themselves, exist under conditions as to light and 
soil very different from those that prevail in the swamp-forests 
and, as regards soil at least, quite unlike those offered by muddy 
banks that shelve under the sea whereon the salt- worts grow, or that 
exist in the swamp-savannahs. This being the case, it is not surpris- 
ing to find, as we did in the preceding chapter, that 40 per cent, of the 
Sundribun sea-face plants are confined to this sea-fence or to these 
sand-hills. 
None of these sea-face plants have been introduced by man, and 
none are likely to have been introduced by water-birds. Frugivorous 
birds may, however, be responsible for the introduction of Capparis 
sepiariay though this is just as likely to have been brought by the sea ; 
oi Allophylus Cobbe \ oi Vith trifolia ; oi Ixora parviflora^ though 
this has more probably been washed down from Upper India by one 
of the rivers ; of both species of Vitex^ though both are common sea- 
coast species in the Andamans and Burma, and may be here sea-intro- 
duced, while, for that matter, F. Negundo at least may have been 
brought down by the rivers ; of Cassytha filiformis, though this, which 
is a frequent parasite on Ipomoea pes-capras on Andaman sea-beaches, 
may have come here by the sea ; of Ficus Rumphii^ though this too 
may be sea-introduced as it is a very common, indeed almost unfailing 
denizen of the corresponding sea-fence on the shores of the Andamans. 
Bird-agency, then, seems unequivocal only in the case of two species. 
Wind-agency is perhaps unequivocal in the case of Naravelia 
zeylanica^ Dolichandrone Rheedei^ and Saccharum spontaneum ; 
it may explain the presence of Aristolochia indica though this has 
more probably been washed down by the rivers, and of Launea 
pinnatifida, though this is more likely to have been brought by the 
tides. 
Species at the sea-face almost certainly washed down by rivers 
are Cassia Sophera^ Tamarix, Crotalaria retusa, C. Saltiana and 
C verrucosa^ Aneilemay Lippia geminatay Cyperus tegetiformis) those 
probably introduced here by this agency are Odina Wodter, Derris 
scandens, Ixora parvifloruy Aristolochia indicay Trewia nudiflora. 
