242 FLORA INDICA. 



tially dry in the winter months. They extend from the very 

 base of the Khasia and eastern extremity of the Cachar dis- 

 trict, southward to the Tippera hills and Sunderbunds, and 

 westward to the Megna and considerably beyond it, thus 

 forming a freshwater continuation of the Sunderbunds, and 

 affording a free water-communication in every direction. The 

 villages, and occasionally large towns, which are scattered 

 over the surface of the Jheels, generally occupy the banks of 

 the principal rivers; these have defined courses in the dry 

 season, their banks always being several feet higher than the 

 mean level of the inundated country. 



Extensive sand-banks, covered in winter with a short sward 

 of creeping grasses and annual weeds, run along the banks of 

 the largest streams, and shift their position with every flood. 

 The remainder of the surface is occupied by grassy marshes 

 covered in winter with rice crops, and in summer with water, 

 upon which immense floating islands of matted grasses and 

 sedges are seen in every direction, gradually carried towards 

 the sea by an almost imperceptible current. The principal 

 floating grasses are Oplismenus stagninus and Pharus arista- 

 tus, which together form the mass of each islet; and along 

 with these "occur Azolla, Salvinia, Utricularia, Villarsia of two 

 species, Jussieua, Trapa, Pistia, and several aquatic Scrophu- 



larinea. 



In shallower water, Vallisneria, Hydrilla, Potamogeton, 

 Damasonium, several Nymphace, Myriophylla, and Ceratopte- 

 res carpet the bottom, whilst Conferva and the many tribes 

 of fresh-water Algae, so common in temperate latitudes, are 



comparatively rare. 



In the marshes the principal grasses are Panica, Paspala, 

 and their allies, with tall Andropogons, Sacchara, Erianthus, 

 Arundo, Apluda, and Rottbcellia in the greatest abundance- 

 Mixed with these are Typha, Scleria and numerous Cyperi, 



but no large Junci. 



On the banks of the principal streams a fringe of brush- 

 wood consists of Stravadium, Tetranthera, Grewia, various 



