Environmental Characteristics: In the coastal region of the Bay of Bengal the soil is saline, muddy and water logged. Besides daily high and low tides is an important factor. All these environmental factors are unfavourable for plants. To overcome these adverse conditions, plants, those grow here, develop certain adaptations such as:
(1) Due to salinity of the soil their root cannot enter very deep in the soil. So to protect from wind and storm many plants (e.g. Sundari) develop root buttresses.
(2) Many plants (e.g. Boro) develop stilt roots.
(3) Due to inadequate oxygen supply in the soil many plants e.g. Sundari, Keora, etc. develop Pneumatophores or respiratory roots, originate from the underground horizontal branch roots lying parallel with the soil surface. There are air pores and air spaces in these respiratory roots, which help the exchange of gasses.
(4) As seeds are washed out by tides, in some plants there occurs viviparous germination.
Hence seed germinates when it is in the fruits and fall on the earth when the root become elongated and heavy. Viviparous germination found in plants such as Boro, Khosi, Hargoja etc. Sundari and Geowa do not have viviparous germination.