Rhizophora mangle

Rhizophora mangle L.

Common Names: Red Mangrove

Habit: Rhizophora mangle grows as a low shrub to trees over 10 meters in height.  They produce adventitious prop roots that become in tangled with neighboring plants forming a dense barrier of roots that can be at times impossible to transverse.

The leaves are opposite but cluster at the ends of branches.  The leaf margin is entire and are 5-15 cm long to 6 cm wide.

The complete perfect, actinomorphic flowers are arranged in 2-3 flowered clusters. The calyx has 4 involute, keeled, green sepals. The corolla has 4 pale yellow petals. There are 8 stamens that are clustered around the style. The fruit is a drupe that hangs down.  It is leathery and has a single seed.  The seed germinates while still attached to the parent plant (viviparous).  The pendulant seedlings root emerges and when the seedling drops from the plant the root will embed itself in the substrate.

Habitat: Rhizophora mangle grows in saline and brackish environment along coastlines, estuaries and inland lakes near the shoreline.  The roots are suberized and form a barrier to salt intake.  R. mangle can exclude over 95 % of the salt in the water they grow in.

Distribution: Rhizophora mangle occurs on all island groupings in the Lucayan Archipelago as well as throughout the Caribbean, the coastlines of central and south America, Africa and the pacific islands.

General ecological importance: Rhizophora mangle wetlands are considered to be builders of land and protectors of the shorelines.  The dense intertwined roots trap organic debris and create a form of peat material. Additionally they protect shorelines during hurricanes.  Along coastlines and estuaries they form critically important nursing grounds for many of the fish and other marine animals that inhabit reef systems.

The prop roots are an ecological adaptation to low oxygen environments.  They are able to absorb oxygen through their roots for biological processes.