Perepat (Sonneratia alba)

The Perepat (Sonneratia alba) is a nationally common mangrove tree from the family Lythraceae. As with the other Sonneratia species it is also commonly called "Mangrove Apple".


It is commonly found in most, if not all, the mangrove forests of Singapore.


This is a pioneering species, usually found at the front of mangrove forest, preferring sandy substrates.


The trunk is cream-coloured to brown, with fine fissures on the bark. The cable roots radiating from the tree underground arise at various intervals to form conical pneumatophores. These roots help the plant breathe air, which is scarce in the waterlogged soil. The roots spread over a wide area to help stabilise the tree on the unstable ground. Like other Sonneratia species, S. alba relies on its roots to exclude salt from entering the plant through a process called ultrafiltration.


It has simple, opposite leaves that are broadly drop-shaped with rounded tips.


The sepals of the flower are red inside and green outside. Petals are small and white, and are shed quickly.


The flowers usually bloom at night, revealing numerous white stamens which are shed the next morning. They are pollinated by nectar-feeding bats and moths at night, and birds in the morning.


The fruits are somewhat pear-shaped with persistent sepals whose tips bend back towards the stalk. Each fruit contains numerous seeds which has air-bearing tissues, allowing them to float and be dispersed by water.

The fruits and leaves are edible, while the wood is used for various construction purposes, such as the construction of buildings, bridges, boats, wooden tools and furniture.

References

• Chong, K. Y., H. T. W. Tan & R. T. Corlett, 2009. A Checklist of the Total Vascular Plant Flora of Singapore: Native, Naturalised and Cultivated Species. Raffles Museum of Biodiversity Research, National University of Singapore. Singapore. 273 pp.
• Giesen, W., S. Wulffraat, M. Zieren & L. Scholten. 2006. Mangrove guidebook for Southeast Asia. RAP Publication 2006/07. FAO Regional Office for Asia and the Pacific & Wetlands International. Bangkok. 769 pp.
• Ng, P. K. L. & N. Sivasothi. 1999. A guide to the mangroves of Singapore 1 : the ecosystem & plant diversity. Singapore Science Centre. Singapore. 168 pp.