INTllODUCTOUY ESSAY. 165 



Assam, is found occasionally iu the eastern districts. The 

 indigenous flora is much more extensive than that of the 

 upper Gangetic plain, comprising all the species which grow 

 there except those belonging to the Egyptian or arid flora, 

 besides many others which are not found to the north-west. 

 Perns are numerous, and a few epiphytical Orchideoe are 

 found upon the trees, Vanda RoxburgUi being the most com- 

 mon. One of the most remarkable forms is a species of rose 

 {R. involucrata) , which is common in the grassy jungles of 

 the northern parts of Bengal. Many peninsular species 

 which are prevented by the cold of winter from extending 

 northward to the upper Gangetic plain are abundant in Ben- 

 gal. The common shrubs are species of Zizyphus, Adhatoda, 

 Calotropis, Carissa, Melastoma, Alangium, Stravadium, Tetran- 

 thera, Antidesma, and G'uatteria suberosa. Pedalium Murex, 

 Tiaridium Indicum, Trichodesma Zeylanicum, Coldenia pro- 

 cumbens, Thespis divaricata, and Tiliacora acuminata may be 

 mentioned as instances of peninsular forms which are equally 

 common in Bengal, but are not found in the upper Gangetic 

 plain. One of the most curious natives of Bengal is Ethulia 

 divaricata, a tropical African plant, which is found nowhere 

 else in India. The flora of Bengal does not exhibit much 

 afiinity with that of the Malayan Peninsula, containing no 

 Cycas, Oaks, nor Nutmegs, though these all grow in Chitta- 

 gong very little to the eastward, and in the Khasia hills on 

 the north-east frontier. 



Within the influence of the tides the delta of the Ganges 

 is covered with a dense jungle of trees peculiar to salt-marshes, 

 called the Sunderbunds. This is most largely developed in 

 the western parts of the delta, where the rise and fall of the 

 tides are not considerable, and where there is but little influx 

 of fresh water. To the eastward, near the mouth of the Megna, 

 the bay is almost fresh, and its shores are muddy without 

 vegetation. The rise and fall of the tides are here so consi- 

 derable, that there is not the same facility for the growth of 

 shrub and trees along the margin of the ocean, that there is 



