280 N ANN AND ALE. 



coasts. Single plants of this species spring up every autumn in the sandy patches 

 on the southern side of the island from, seeds left by the floods, but perish long 

 before the returning floods, without reproducing themselves or even flowering. 



lyater on, by the beginning of April, other plants establish themselves on the 

 sandy foreshore, but not all by the same means. The nodular roots of a small sedge 

 remain alive at the bottom of the lake near, but a little above, the low-water level. 

 These sprout and form a coarse turf as they are exposed by the complete retreat of 

 the floods^ but I have never found the species in flower. Doubtless the seeds of 

 certain haloph^^tic plants remain dormant beneath the water in crevices in the rocks 

 and under stones, for both Crcssa cretica and Suaeda nudiilora spring up, at first 

 appearing as very small plants, a little above low-water level, the latter species later 

 in the year than the former. 



Other plants are introduced anew each year by flood-carried seeds or rooting 

 stems. One of the commonest of these, though it is represented merely by scattered 

 plants on the lower parts of the foreshore, is the common dhub-grass [Cynodon 

 dactyl on), stocks of which are brought as such and flourish among the rotting algae, 

 without, however, flowering. Fragments of Phragmites are also cast ashore in the 

 flood season and attempt to grow, but never with final success. 



Yet other plants, which appear on the sandy foreshore latest of all, are introduced 

 by aerial agencies. Few of these are immigrants from other parts of the island, the 

 most conspicuous that ma^^ so be classed being Datura fastuosa and the little sedge, 

 Cyperus compressus, the latter conspicuous on account of its bright green colour and 

 abundance. The Datura flourishes in this situation in the hot weather but attains 

 its maxiinum development and full flowering shortly before the return of the floods, 

 in which it disappears. The most conspicuous, however, of all the members of this 

 seasonal association is Coldcnia procumhens, which has not been found in any other 

 zone on Barkuda. It forms in March and April large circular mats, which are often 

 contiguous, and thus covers considerable areas. By the end of June the majority of 

 these are black and dead, probably owing to the heat of the sand, for plants in the 

 shade of Datura bushes survive longer. Other herbs found on the foreshore in the 

 dry sea?on attain no more than a precarious existence as scattered individuals. On 

 Barkuda I have never seen the rush-like Scirpits littoralis, which forms a large scir- 

 petum on the more sheltered part of the foreshore of Cherriakuda, where soft mud 

 occurs. 



The Pong ami a Zone. 



The ring of Pojtgamia glabra that surrounds the island at high-flood level 

 is almost unbroken on the northern shore, where it is three or four trees deep and is 

 only interrupted by occasional trees of Azadirachta and Crataeva, The individuals 

 of these two species are wedged in singly among those of the Pongamia and it 

 is a striking fact that in this position they are as a rule almost overwhelmed by dense 

 masses of creepers, the commonest of which are the Leguminosae, Derris scandens and 

 Acacia intzia. Capparis Roxburghii is also found in this zone onNim trees, which are 

 sometimes parasitized by Cassytha filiformis. Neither creeper nor parasite was found 



