1S93.] R. L. Heinig — Blind root-suckers of the Sunderbans. 161 



Keora sends out very long- roots into the mud of river beds. These 

 roots act as spurs deflecting the course of the current, causing accu- 

 mulations of silt, and sometimes leading to the complete silting up 

 of rivers. Innumerable suckers proceed from these roots up to dis- 

 tances of 150 feet and more from the parent tree, and aid in fixing 

 whatever silt has accumulated, and inducing the deposit of more. These 

 suckers are exposed at low tide, but are subjected to long-continued 

 submergence daily until the bank has risen sufficiently to allow the 

 tops to remain above the level of high tide. 



Baen suckers are of exceptional interest. Their form and flexibility 

 render them almost useless as agents for the prevention of erosion and 

 the arrest of silt, seeds, and wood debris ; and it is certain that they 

 do not have the effect of enabling trees of this species to maintain a 

 vertical position. Baen trees after attaining a girth of 2 to 3 feet, incline 

 from the vertical. In the case of large trees, 15 feet in girth and more, 

 the inclination from the vertical is often considerable ; but the trees 

 of this size have long since passed their maturity, and are merely light, 

 hollow shells. 



The most interesting fact regarding the root-suckers of this species 

 is that they have been found, on examination of the internal structure, 

 to contain vessels that are supposed to serve as passages for the con- 

 veyance of atmospheric air to the roots. 



It has been remarked that the top-layer of alluvial mud, a very 

 fine silt, excludes atmospheric air from the lower stratum of miasmic 

 mud wherein the wood debris of the forests decomposes and large 

 quantities of gas are generated. The fact has also been noted that 

 the root-suckers continue to make upward growth until their tops are 

 above high-water level. It is accordingly considered probable that 

 the root-suckers of all the species that produce these curious processes 

 not only discharge the mechanical functions already referred to, but are 

 provided with a structure that enables them to supply atmospheric 

 air to the roots. 



