mangrove

mangrove, large tropical evergreen tree, genus Rhizophora, that grows on muddy tidal flats and along protected ocean shorelines. Mangroves are most abundant in tropical Asia, Africa, and the islands of the SW Pacific. The American, or red, mangrove (Rhizophora mangle) is found along the muddy shores and in the everglades of the Florida peninsula and on other tropical American coast lines.

Many mangroves produce from their trunks aerial roots that become embedded in the mud and form a tangled network; this serves both as a prop for the tree and as a means of aerating the root system. Such roots also form a base for the deposit of silt and other material carried by the tides, and thus land is built up which is gradually invaded by other vegetation. Mangrove forests also can protect inland coastal areas by absorbing the effects of storm and some tsunami waves, but mangroves have been harvested destructively on a large scale in some areas, and their forests replaced in many cases by rice paddies, aquaculture facilities, and oil palm plantations. The bark is a rich source of tannins, and the wood is used for wharf pilings and other purposes.

Some mangrove species lack prop roots but have special pores on their branching root system for obtaining air. The mangrove fruit is a conical reddish brown berry. Its single seed germinates inside the fruit while it is still on the tree, forming a large, pointed primary root that quickly anchors the seedling in the mud when the fruit is dropped.

The name mangrove is also applied to other unrelated constituents of mangrove vegetation, such as Avicennia nitida, a bush of the vervain family, called black mangrove. True mangroves are classified in the division Magnoliophyta, class Magnoliopsida, order Rhizophorales, family Rhizophoraceae.

See P. B. Tomlinson, The Botany of Mangroves (1986).

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