White Mangrove loves brackish wetlands

Know your islands

Laguncularia racemosa

Laguncularia racemosa

Grand Cayman’s Central Mangrove Wetland is the ecological heart of Grand Cayman.

It is critical to so many important natural processes that the National Trust for the Cayman Islands considers its long term protection to be one of the fundamental requirements for the well-being of future generations in the Cayman Islands.

The following is taken from Wild Trees in the Cayman Islands by Fred Burton, with illustrations by Penny Clifford; Photographs by Marnie Laing.

White Mangrove

Laguncularia racemosa

White Mangrove is a tree of brackish wetlands, unable to tolerate extremely salty water.

It grows with a characteristically straight trunk, with sulphur-yellow, orange, pinkish and grey lichens which make the trunk appear pale at a distance.

The bark splits and spreads into broad, rough vertical bands, eventually shedding woody vertical strips.

Trees with multiple trunks are quite common.

You can recognize White Mangrove quite clearly by examining a leaf closely.

The upper side of the leaf stalk has a pair of swollen glands with a minute dot in the centre of each.

The leaves are yellowish green, and if you hold one up to the light you can see dark spots near the leaf edges.

Like Black Mangrove, White Mangrove has breathing roots or pneumatophores, but these are much shorter than in Black Mangrove and grow in tight clusters: they are nowhere near as obvious. The main roots can often be seen spreading from the trunk slightly above the ground level.

White Mangrove produces abundant seeds late in the wet season, when the wetlands are likely to be deeply flooded.

The seeds float and can survive in water for weeks or even months, slowly germinating and producing a short rootlet in preparation for contact with the ground.

Storms and overland flow after heavy rain can transport these floating seeds over long distances, and this makes White Mangrove an efficient colonizer of new sites. It is especially successful in areas of mangrove damaged by storms or human activities.

Common in wetlands in all three of the Cayman Islands, White Mangrove also is native throughout the American tropics, and to West Africa.

It can be propagated by air layers, but this is very slow.

Grow Cayman Plants and encourage Cayman Wildlife! For more information, to share your knowledge or if you would like to get involved with the many activities in the National Trust’s Know Your Islands Program, please visit www.nationaltrust.org.ky, or call 949-0121.

Last week’s answer: Daub is a limestone based plaster, made by burning coral rocks with various woods in a lime kiln.

Trivia question: Approximately how many acres of the Central Mangrove Wetland are protected through the Marine Parks Law?

Look for the answer in next week’s feature!

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