249 



Excce:aria Agnllocha, 



Cerbera Odottam. 



Scaevola. 



Clerodendrcn inerme. 



Erythrina indica, 



Pongamia glabra. 



Casuarina equisetifolia. 



Pandanus tectorius. 



225. The principal types of Riparian 



Indian forests have now been considered in detail above, and it F 01 ^ 3 * 8 - 

 only remains to briefly mention the sub-type, often called 

 riparian forest, which is found along the banks and in the beds 

 of rivers and streams and in swampy places. Forests in such 

 localities usually have an abundant supply of fresh water 

 available in the soil, and consequently the belt of land imme- 

 diately bordering perennial streams in the arid region may be 

 able to support forest of the ordinary deciduous type, while 

 similar streams in the zone of deciduous forests may be fringed 

 with more or less evergreen forest. At the same time the 

 conditions under v hich the plants of these forests exist are 

 often peculiar in many respects. 



The ground on which they grow is, for instance, often liable 

 to more of less prolonged submersion in water at certain seasons 

 which, by causing stagnation of water around the roots, may 

 eiiectually prevent the latter from performing their functions 

 on account of the want of sufficient oxygen. A very common 

 species in riparian tracts is Ficus cjomerata which sheds its 

 leaves during the rainy season, possibly owing to the roots 

 being then unable to perform their normal functions. 



In addition to this also many of our Indian rivers and streams 

 are entirely dry for several months in the year, when the sandy 

 shingly soil in and near their beds becomes dried and excessively 

 heated to a considerable depth. Other factors to be consi- 

 dered also are the action of floods in washing away the soil 

 and exposing the roots and the utility of water as a seed distri- 

 butor, those species possessing devices favouring this mpde of 

 seed-dispersion having an advantage in the struggle for exist- 

 ence in riparian tracts, as has been noted above in the case 

 of Sissoo and Khair. It is therefore not surprising that many 

 species which are characteristic of riparian tracts, are not often 

 iound elsewhere. Among such may be mentioned 

 Anogeissus acuminata. 

 Barrincjtonia acutangula. 

 Eugenia sp. 



