THE PA LIPOTROPICS 183 



At high tide the mangroves appear to rest on the Burface of the 



water, but with the ebbing tide the shiny black mud banks are 

 exposed, showing the fantastic tangle of stilt-root-. These aerial 

 roots are important aerating organs for the roots buried in the 

 mud; the white mangrove (Avicennia), sends up myriads of Blender 

 aerial roots or "pneumatophores" for the same purpose. 



The seaward extension of the mangrove formation may be 

 rapid. The seed germinates while still attached to the parenl 

 tree, and the seedling develops into an elongated, rod-like body, 

 ending in a stout root. The young plant, detached from the branch, 

 falls like a plummet, the root penetrating deep into the mud, thus 

 firmly anchoring the seedling mangrove, which quickly forma 

 a bush of considerable size. 



Back of the swamp, as noted for West Africa, there is built 

 up a strip of drier soil which gradually adds to the mainland. 



The great delta area of the Ganges back of the mangroves is 

 largely a region of fresh water marshes and wet forest, support- 

 ing a great variety of hygrophilous plants, among them many 



palms. 



The low vegetation, with brackish swamps, chiefly composed 

 of dwarf palms and mangroves, does not give an impression of 

 tropical luxuriance, and it is not until the sandy spits and marshy 

 jungles of the delta are passed, that the full luxuriance of the 

 tropical vegetation is seen. In the delta of the Ganges, as in 

 other tidal swamps of the East, the Nipa-palm is a conspicuous 



feature. 1 



Directly north of Calcutta is the well-known mountain station 

 Darjiling, commanding probably the finest mountain-panorama 

 in the world, as it comprises a perfect view of the main range of 

 the Himalaya, with the giant Kinchinjunga in the centre. 



The journey from Calcutta to Darjiling is a most interesting 

 one to the botanist. A line running from Calcutta to Darjiling 

 has been proposed as a division between two quite dissimilar 

 floras, that to the east being predominantly Malayan, while west- 

 ward there is a marked infusion of African types. 



Proceeding northward from Calcutta the rank luxuriance of 

 the delta country is succeeded by the drier portion of the ( rangetic 

 plain and still further northward the "Terai' is reached, the 



1 Hooker, J. D., Himalayan Journals, pp. 1-2, I s 



