The Bakau Pasir (Rhizophora stylosa) is a nationally vulnerable mangrove tree from the family Rhizophoraceae.
This mangrove tree can be seen at Pulau Tekong, Pulau Ubin, St John's Island, Sentosa and Pulau Semakau and Berlayar Creek, among others.
It grows on a variety of habitats. In Singapore, it usually occurs along sandy shores as a pioneer species, as it is better at resisting the surf than the other species. It can also be found along tidal rivers and prawn ponds. The bark is dark grey or dark brown, and prop roots and stilt roots can be seen at the lower part of the tree. 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 mangrove species from the family Rhizophoraceae, R. stylosa relies on its roots to exclude salt from entering the plant through a process called ultrafiltration.
It has simple, opposite, leathery leaves that are elliptic with pointed tips, clustering towards the end of the branch. The leaf buds are cover by light green stipules.
Tiny black dots can be seen on the underside of the leaves, as in the case of other Rhizophora species.
Stalks of flower heads are long and forked 2-5 times, and 4-14 flowers on long individual stalks up to 5 cm long. The flower has a long style, 4-6 mm long.
Vivipary is observed in this plant, as with the other mangrove species from the family Rhizophoraceae. This is a condition whereby the embryo grows and break through the seed coat and the fruit wall while still attached to the parent plant. Hence, the thin and long structures seen hanging from the trees are the seedlings, not fruits. The hypocotyl can be more than 50cm long, rough and warty, with a pointed tip, though most are less than 40cm.
Mature seedlings are dispersed by water and have a greenish collar. The seedling floats horizontally for a few weeks, during which the root (lower part) will absorb water and become heavier, eventually causing the seedling to tip and float vertically. As the tide goes down, the vertically-oriented seedling will sink into the mud or other suitable substrates. Most of the seedlings, however, end up being washed ashore or eaten by animals. As the seedlings are thin and long, many of them also ended up settling directly under the parent tree, as they drop and poke into the soil below.
The wood is hard and heavy, and is used for making charcoal.
References
This mangrove tree can be seen at Pulau Tekong, Pulau Ubin, St John's Island, Sentosa and Pulau Semakau and Berlayar Creek, among others.
It grows on a variety of habitats. In Singapore, it usually occurs along sandy shores as a pioneer species, as it is better at resisting the surf than the other species. It can also be found along tidal rivers and prawn ponds. The bark is dark grey or dark brown, and prop roots and stilt roots can be seen at the lower part of the tree. 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 mangrove species from the family Rhizophoraceae, R. stylosa relies on its roots to exclude salt from entering the plant through a process called ultrafiltration.
It has simple, opposite, leathery leaves that are elliptic with pointed tips, clustering towards the end of the branch. The leaf buds are cover by light green stipules.
Tiny black dots can be seen on the underside of the leaves, as in the case of other Rhizophora species.
Stalks of flower heads are long and forked 2-5 times, and 4-14 flowers on long individual stalks up to 5 cm long. The flower has a long style, 4-6 mm long.
Vivipary is observed in this plant, as with the other mangrove species from the family Rhizophoraceae. This is a condition whereby the embryo grows and break through the seed coat and the fruit wall while still attached to the parent plant. Hence, the thin and long structures seen hanging from the trees are the seedlings, not fruits. The hypocotyl can be more than 50cm long, rough and warty, with a pointed tip, though most are less than 40cm.
Mature seedlings are dispersed by water and have a greenish collar. The seedling floats horizontally for a few weeks, during which the root (lower part) will absorb water and become heavier, eventually causing the seedling to tip and float vertically. As the tide goes down, the vertically-oriented seedling will sink into the mud or other suitable substrates. Most of the seedlings, however, end up being washed ashore or eaten by animals. As the seedlings are thin and long, many of them also ended up settling directly under the parent tree, as they drop and poke into the soil below.
The wood is hard and heavy, and is used for making charcoal.
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.
- http://www.mangrove.my/page.php?pageid=mangrove
No comments:
Post a Comment