Man Oh Man Oh Mangrove

Mangroves


Honeymoon Island Florida

Take the Mangal Cay Mangrove Island tour

The Red mangrove (Rhizophora mangle) is the tallest of all local species. It grows to heights over 80 feet tall (25m). It has large broad leaves grow to 5 inches (12cm) and terminate with a blunt point. The leaves are waxy, dark green above and pale green below. The trunk and limbs have grey bark that covers a dark red wood. The key characteristics of the Red mangrove are the "prop roots" derived from the trunk and “drop roots” from the branches. The seedling or propagule is almost 6 inches long (l5 cm) and cigar-shaped.

The second tallest species is the Black mangrove (Avicennia germinans), reaching heights over 65 feet(20m). The elliptical, green leaves approach lengths of 4 inches (10cm) and are often encrusted with salt. The leaf undersurface is covered with dense hairs. The bark is dark and scaly. The key characteristics of the Black mangroves are the aerial roots known as pneumatophores born from underground horizontal cable roots. Living in oxygen deprived sediment more than 10,000 pneumatophores may be found on a single tree. The propagules are approximately one inch (2-3cm) long and lima bean shaped.

The White mangrove (Laguncularia racemosa) is the smallest species existing as a tree or shrub with maximum heights of 50 feet (l5 m). The leaf shape is a broad, flat oval rounded at both ends. Leaf lengths approach three inches (7cm). Two glands are found at the base of each leaf at the apex of the petiole. When growing in oxygen deprived sediment the White mangrove often develop peg roots which are similar to pneumatophores except they are shorter and more stout in appearance. The propagules are very small, usually less than 0.2 inches (0.5 cm).

The Buttonwood (Conocarpus erectus) is an associate of the community, but is more frequently found in the upland transitional zone. Its pointed leaves possess salt glands as openings alternating along the midrib on the underside of the leaf. Rough bark exists on older trees which is often covered with epiphytes (plants which live on other plants). Rather than producing seedlings that germinate on the parent tree, buttonwoods flower with the formation of a button-like seed case.

SEACAMP ASSOCIATION, INC. 1998 Florida Department of Education

Discover Life in the Mangrove

Black and White mangroves regulate ionic concentration by excreting salt through glands on the leaf surface.

Lenticels and spongy tissue in red mangrove prop roots and modified branches facilitates gas
(oxygen) exchange.

In Black mangroves, spongy pneumatophores (up to l0,000 per tree) extend up to 20 cm above the sediment.

What is a propagule?

The red mangrove flowers mostly during the summer months. The long cigar shaped propagules are often found hanging on the tree all year long. The black mangrove flowers all summer long with the lima bean shaped propagules produced during late summer and early fall. The white mangrove flowers mid to late summer with small green pea shaped propagules produced a month later.

Hurricanes and Mangroves... check this out

A REALLY COMPLETE STUDY FROM THE Earth Encyclopedia on mangroves.

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