Mangroves are shrubs or small trees that grow in saline or brackish water. They are salt-tolerant Halophytes which are adapted to life in harsh coastal low oxygen conditions of waterlogged mud. They have a complex salt filtration and root system to cope with salt water immersion and wave action.
Mangrove seeds are bouyant and germinate while still attached to the parent tree. Once germinated, the seedlings either within the fruit or out through the fruit to form a propagule, a ready-to-go seedling which produces its own food through photosynthesis.
Mature propagules drop into the water and are transported to far distances. It floats vertically rather than horizontally until they reached a muddy bottom which they are lodged and grow upward and start a shoot.