Mangroves are associated with wet, muddy and silty sediment. This species of mangrove has both aerial prop roots and stilt root which are designed to resist large waves and tropical storms. They are used to stabilise soil, to protect the coastline from storms, and to provide habitat for marine species. They also improve the water quality in nearshore environments. Parts of the plant can be used for traditional medicines and mangrove forests can be used as a sanctuary during cyclones. Natongtong grows up to 40 m in height, though it commonly reaches 5 to 8 m. The bark is grey to dark grey and heavily fissured, although it can occasionally be red-brown and smooth.
Leaves are light or dark green, opposite, simple, egg-shaped and leathery with a distinct sharp pointed tip that is 1 to 7 mm long. The upper leaf is smooth and shiny. Mature leaves are 6 to 19 cm long and 3 to 10 cm wide. The leaf stalks are reddish.
The flower clusters have few to many joint and one to many buds per cluster. The sepals of the flower, that encloses the petals and protects the flower bud, are typically pale yellow at maturity. The flower buds are egg-shaped, changing from green (immature) to pale yellowish green (mature). Buds are 1 to 2 cm long and 1 cm wide. There are generally four petals that are pointed at both ends to linear, with a creamy white colour, and are 10 mm long and 2 mm wide. Petals are arranged in a cross-shaped pattern. The stamens are pale yellow.
At maturity, the fruit are pear-shaped, elongate, with a smooth brown surface. The smaller end points down. Mature fruit are located in leaf axils 8 nodes down from the apical (end of leaf distant from the branch) shoot. Seeds are hidden in the mature fruit. One to occasionally two seedlings are produced from the fruit, emerging from the smaller end while the fruit is still attached to the parent plant.
When to Look
Where to Look
Natongtong is the Bislama word for mangrove, so it encompasses many species. There is also the potential for verbal confusion with Wild Natongtong, which is actually Cryptocarpa turbinate, a forest species.
Stilt mangroves can be distinguished from red mangroves species by the presence of a spiked, sharp pointed tip at the leaf apex. Other Rhizophora species have an under surface with unevenly spread cork wart spots.
Other stilt mangroves:
R. mucronata and R. stylosa have slender bracts at the base of mature buds (other stilt mangroves have bracts almost as wide or wider than their length). R. apiculate differs in that it has swollen (wider than long), corky brown bracts, one flower cluster joint, and node position of mature buds and flowers in leaf axils at 6-11 nodes down from the apical shoot. R. apiculata is more prevalent in estuaries influenced by larger and more continuous freshwater flows. Hybridization between the species is known.