Mangrove, a common name for three or four tropical plants, but mainly applied to species of rhizophora (Gr. , a root, and , to bear), a genus so called on account of the aerial roots borne by the plants; the genua gives its name to the small family of rhizophoraceae, which is nearly related to the myrtle familv. There are but few species, the best known of which is R. Mangle, a plant common in tropical countries; its northern limits upon this continent are southern Florida on the Atlantic and Lower California on the Pacific coast. It is a tree sometimes 40 ft. high, but usually much smaller, with opposite entire, leathery leaves, and axillary, few-flowered clusters of showy flowers; the persistent calyx has an obovate tube and a four-lobed limb; the yellow petals are four, thick, notched at the apex, and woolly on the margins; stamens eight; ovary two-celled with two ovules in each cell; fruit one-celled, indehis-cent, at length perforated by the radicle of the embryo, which germinates while the fruit is still upon the tree. The mangrove is found in muddy localities directly upon the seashore, where it forms impenetrable thickets; its manner of growth is like that of the banian tree in miniature, as the stem and branches produce long slender roots, which finally reach the earth and be-comoiixed. The mangrove not only prevents the encroachments of the sea upon the land but acts an aggressive part in wrestling land from the sea; the seeds, which might be washed away if they fell as soon as ripe, germinate while yet attached to the stem, and when one falls it is already provided with a long radicle; in fact they are not properly any longer seeds, but young plants, which when they drop into the mud are ready to grow at once; after the young tree has formed a stem and head of branches, it is then by means of its aerial roots enabled to spread and occupy more territory, and thus advance seaward, while its fruit will drop beyond the line of the parent tree and new plants be produced further from dry land.
The tangled mass of stems and roots in a mangrove thicket retains the debris from the land that may be brought down by floods, and thus upon the land side of the grove solid ground is gradually formed. From the great quantity of decaying vegetable matter collected in a mangrove thicket, such localities are highly malarious. The account of oysters growing upon trees is not, as has been supposed, a traveller's fable, for the submerged portions of the branch-like roots of the mangrove are often studded with these and other mollusks, and when the tide recedes oysters may be literally gathered from trees. Other species are found on the Malabar coast, and one is found on the Feejee and neighboring islands. The wood of the mangroves is tough, hard, and durable in the water; hence it is employed for boat building, a use for which the natural curves of its branches and its numerous knees especially adapt it. The bark contains a large amount of tannin, and is used all over the West Indies in the preparation of leather, as well as by dyers, giving with different mordants slate-colored and various brown tints.
Occasional shipments of the bark have been made to England, but as there are many products which are much richer in tannin in proportion to their bulk, it is not likely to become a regular article of commerce. The fruit of the common mangrove is ovate and crowned with the persistent calyx, and said to be sweet and edible; its fermented juice makes a kind of light wine.
Fruit of Mangrove.