Black Mangrove
Black Mangrove growing in Guanacaste Province, Costa Rica
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Lamiales
Family:	Acanthaceae
Genus:	Avicennia
Species:	A. germinans
Binomial name
Avicennia germinans L.
Synonyms
Avicennia nitida Jacq.

Black Mangrove (Avicennia germinans) is a species of flowering plant in the Acanthus family, Acanthaceae.

A free-standing Black Mangrove tree growing in shallow water in the backcountry of the Cape Sable area of Everglades National Park.

A. germinans grows in tropical and sub-tropical regions of the Americas, on both Atlantic and Pacific coasts, and on the Atlantic coast of tropical Africa, where it thrives on the sandy and muddy shores that seawater reaches. It can grow to heights of 15 metres (49 ft) in the tropics, but becomes small and shrub-like at the northern limits of its range. Black Mangrove is common throughout coastal areas of Texas and Florida and ranges as far north as southern Louisiana and coastal Georgia in the United States.

Like many other mangrove species, it reproduces by vivipary. Seeds are encased in a fruit which reveals the germinated seedling when it falls into the water.

Unlike other mangrove species it does not grow on prop roots, but possesses pneumatophores that allow its roots to breathe even when submerged. It is a hardy species and expels absorbed salt mainly from its leathery leaves.

The name Black Mangrove refers to the color of the trunk and heartwood. The leaves often appear whitish from the salt excreted at night and on cloudy days. It is often found in its native range with the Red Mangrove and the White Mangrove. White Mangroves grow inland from Black Mangroves which themselves grow inland from Red Mangroves. The three species work together to stabilize the shoreline, provide buffers from storm surges, trap debris and detritus brought in by tides, and provide feeding, breeding, and nursery grounds for a great variety of fish, shellfish, birds, and other wildlife.

[edit] Growth

The Black Mangrove grows just above the high tide in coastal lagoons and brackish water estuaries. It can reach 10–15 m (33–49 ft) in height, although it is a small shrub in the northern (colder) extent of its range. The seeds germinate in mid-summer but may be seen all year on the trees. The seeds can remain viable for over a year once released.

[edit] Wood

The heartwood is dark-brown to black while the sapwood is yellow-brown. It has the unusual property of having less dense heartwood than sapwood. The sapwood sinks in water while the heartwood floats. The wood is strong, heavy, and hard. The wood is difficult to work due to its interlocked grain and somewhat difficult to finish due to its oily texture. Uses include posts, pilings, charcoal, and fuel. In spite of the fact that the tree grows in a marine environment, the dry wood is subject to attack by marine borers and termites. Like many species, Black Mangrove contains tannin in the bark and has been used to tan leather products.

[edit] See also

• List of honey plants

[edit] References

• Haehle, Robert (1999). Native Florida Plants. Houston: Gulf Publishing Company. ISBN 0-88415-425-4. 

[edit] External links

• Media related to Avicennia germinans at Wikimedia Commons