Tuesday, November 29, 2011

Identifying the True Mangrove Plants of Singapore

Generally, true mangrove species refer to those that grow only in mangrove environment and are not found in terrestrial plant community. They are adapted to survive in saline, waterlogged and anaerobic conditions. Based on Tomlinson’s list, Singapore has 21 major mangrove species and 9 minor mangrove species. During my mangrove exploration, I have develop some kind of an ID key for these 30 species in my mind, and thought I will share it here. It may appear amateurish to the real mangrove experts, but should be useful to the lay people who are interested in mangrove plants :)

There are 6 main sections in this key. To use it, just check for the characteristics in the same order listed below and narrow down to the species by elimination. So basically, Just start with asking whether the plant has: A) No Upright Stem(s); B) Compound Leaves; C) Alternate Simple Leaves; or D) Opposite Simple Leaves. If it has opposite leaves, and each leaf is longer than 2cm, then check whether the leaves has: E) Rounded Tips or F) Pointed Tips. Click on the links on the plant names for more details, but note that this guide can only be used in Singapore, as some plant species may have different morphs in other countries.



A) No Upright Stem(s)

1. Long leaflets(60-130cm) with parallel veins.

Nipah Palm (Nypa fruticans)
Nipah Palm (Nypa fruticans) - The only true mangrove palm in Singapore. It is a monocot, and has huge compound leaves up to 9m long. The palm lacks a trunk, but instead, has thick underground rhizomatous forking stems.

2. Mature leaf has blunt tips, sometimes with a small point.

Piai Raya (Acrostichum aureum)
Piai Raya (Acrostichum aureum) - This is a mangrove fern which can grow as tall as 4m. It prefers sunny sites. Like other ferns, they reproduce from spores, and large sporangia cover the undersides of fertile fronds.

3. Mature leaf has elongated pointed tips.

Piai Lasu (Acrostichum speciosum)
Piai Lasu (Acrostichum speciosum) - This mangrove fern grows up to about 1.5m, much shorter than A aureum. It prefers shady areas. Like other ferns, they reproduce from spores, with the sporangia on the undersides of fertile fronds.



B) Compound Leaves

4. Leaflets with rounded tips.

Nyireh Bunga (Xylocarpus granatum)
Nyireh Bunga (Xylocarpus granatum) - This tree can also be recognised by its thin and flaking barks. The fruits are round, about the size of a small coconut.

5. Leaflets with pointed tips.

Nyireh
Nyireh Batu (Xylocarpus moluccensis) - Unlike X. granatum, this tree has fissured bark. The fruits are round, about 10cm across.



C) Alternate Leaves

6. Leaves with silvery undersides.

Dungun (Heritiera littoralis)
Dungun (Heritiera littoralis) - When in bloom, it can be identified by its clusters of numerous tiny cup-shaped flowers. The fruits are woody with a keel on one side.

7. Leaves with pointed tips.

Buta-buta (Excoecaria agallocha)
Buta-buta (Excoecaria agallocha) - Also called "Blind-your-eyes", it has poisonous white sap in its leaves and branches. It bears tiny flowers on catkin-like, elongated clusters. The tree is deciduous.

8. Alternate/subopposite leaves, obovate with prominent yellowish/light green veins.

Kacang-kacang (Aegiceras corniculatum)
Kacang-kacang (Aegiceras corniculatum) - This small tree bears white flowers with protruding anthers and a pinkish style. The fruits ranges from green to pinkish to red in colour, and are strongly curved.

9. Leaves mostly drop-shaped (broader at the tip) and red flowers.

Teruntum Merah (Lumnitzera littorea)
Teruntum Merah (Lumnitzera littorea) - This tree has pretty red flowers, and even the young branches are reddish in colour. The small and somewhat corky fruits may have a reddish tinge as well.

10. Leaves mostly obovate (broadest about 2/3 towards the tip) and white flowers.

Teruntum Putih (Lumnitzera racemosa)
Teruntum Putih (Lumnitzera racemosa) - The leaves of this tree are usually of a fresher green compared to L. littorea. The small fruits are fibrous and compressed sideways, with a prominent persistent style.



D) Opposite Leaves

11. Small leaves not more than 2cm long.

Mentigi (Pemphis acidula)
Mentigi (Pemphis acidula) - This small shrub/tree bears pretty small white flowers. The fruits are small, turning reddish brown as they mature. The tip of the leaves may be pointed or rounded.



E) Opposite Leaves with Rounded Tips

12. Apical bud compressed and rounded.

Chengam (Scyphiphora hydrophyllacea)
Chengam (Scyphiphora hydrophyllacea) - This small tree/shrub may have one or multiple stems. The white flowers occur in dense clusters. The small fruits are cylindrical and green, ribbed along its length.

13. Apical bud compressed and twisted, enclosed in stipules.

Pisang-pisang (Kandelia candel)
Pisang-pisang (Kandelia candel) - The flowers are white and occur in clusters, dichotomously branched. The seedling's hypocotyl has a somewhat pointed tip, and is capped by the persistent sepals whose tips bend backwards towards the stalk.

14. Apical bud compressed and enclosed in stipules. Fruit with textured patterns and seedling with red collar.

Ceriops zippeliana
Ceriops zippeliana - The seedlings of this tree generally hang in various directions. The small flowers are white and turn brown quickly.

15. Apical bud compressed and enclosed in stipules. Fruit plain and seedling with white collar.

Tengar (Ceriops tagal)
Tengar (Ceriops tagal) - The small flowers are white and turn brown quickly, and have 5 thick and claw-like sepals. Unlike C. zippeliana, the seedlings usually occur hanging downwards.

16. Leaves dark green on top, and light brown and velvety below.

Api-api Bulu (Avicennia rumphiana)
Api-api Bulu (Avicennia rumphiana) - Like other Avicennia species, it has pencil-like aerial roots (pneumatophores). The fruits are broadly ovate, covered with short hair, giving it a furry appearance. Flowers are small and yellow, occurring in clusters.

17. Leaves dark green on top and light green below.

Api-api Ludat (Avicennia officinalis)
Api-api Ludat (Avicennia officinalis) - Like other Avicennia species, it has pencil-like pneumatophores. The fruits are broadly ovate with a short beak, covered with short hair, and yellowish-brown in colour. Flowers are small and yellow, occurring in clusters.

18. Leaves broadly drop-shaped/pear-shaped.

Perepat (Sonneratia alba)
Perepat (Sonneratia alba) - Like other Sonneratia species, it has conical pneumatophores. The flower has small and white petals, and numerous white stamens. The fruits are somewhat pear-shaped with persistent sepals whose tips bend back towards the stalk.

19. Leaves broadly ovate, oval or almost round.

Gedabu (Sonneratia ovata)
Gedabu (Sonneratia ovata) - Like other Sonneratia species, it has conical pneumatophores. The flower has numerous white stamens but no petals are absent. The fruits are round, with the calyx enveloping the berry.



F) Opposite Leaves with Pointed Tips

20. Leaves glossy green on top and whitish below. Fruits the shape of elongated inverted teardrops.

Api-api Putih (Avicennia alba)
Api-api Putih (Avicennia alba) - Sometimes confused with A. marina, it is best to confirm the species by looking at the fruits, which are in the shape of elongated inverted teardrops and are whitish/greyish green in colour. Like other Avicennia species, it has pencil-like pneumatophores. It has small yellow flowers, occurring in clusters.

21. Leaves green (with a yellowish tinge) on top and yellow or whitish green below. Young twigs have a squarish cross-section. Fruits the shape of fat inverted teardrops.

Api-api Jambu (Avicennia marina)
Api-api Jambu (Avicennia marina) - Easily confused with A. alba, this species is best confirmed with the fruits, which are in the shape of a fat inverted teardrops and are light green in colour. Like other Avicennia species, it has pencil-like aerial roots. It has small yellow flowers, occurring in clusters.

22. Leaves have a minute, recurved point at the tip.

Berembang (Sonneratia caseolaris)
Berembang (Sonneratia caseolaris) - Like other Sonneratia species, it has conical pneumatophores. The flowers have red petals and numerous stamens. The filaments are either all white, or white in the upper part and red in the lower part. The fruit is persimmon-like with a flattened calyx tube.

23. Narrowly elliptic leaves, undersides covered with small black dots. Apical buds enclosed in thin, pointed, red stipules.

Bakau Minyak (Rhizophora apiculata)
Bakau Minyak (Rhizophora apiculata) - Like other Rhizophora species, prop roots and stilt roots can be seen at the lower part of the tree. The stalks of the flower heads are short, about 1cm long, and each stalk bears 2 stalkless flowers. Mature seedlings have a red collar.

24. Elliptic leaves less than 6.5-12.5cm long, undersides covered with small black dots. Green stipules. Flower has long style, 4-6 mm long.

Bakau Pasir (Rhizophora stylosa)
Bakau Pasir (Rhizophora stylosa) - Like other Rhizophora species, prop roots and stilt roots can be seen at the lower part of the tree. Mature seedlings are dispersed by water and have a greenish collar. Leaves are generally shorter but proportionally broader than R. apiculata.

25. Broadly elliptic leaves more than 11-23cm long, undersides covered with small black dots. Green or red stipules. Flower has short style, 0.5-1.5 mm long.

Bakau Kurap (Rhizophora mucronata)
Bakau Kurap (Rhizophora mucronata) - Like other Rhizophora species, prop roots and stilt roots can be seen at the lower part of the tree. It has red or light green stipules. Mature seedlings are dispersed by water and have a light green or whitish collar. The leaves are much bigger and proportionally broader than the other 2 Rhizophora species.

26. Small flowers with yellow petals. Short and straight calyx lobes.

Lenggadai (Bruguiera parviflora)
Lenggadai (Bruguiera parviflora) - Like other Bruguiera species, the bark is covered with small lenticels, and the tree has knee roots.

27. Small flowers with white petals. Calyx lobes bend backwards on seedlings.

Bakau Putih (Bruguiera cylindrica)
Bakau Putih (Bruguiera cylindrica) - Like other Bruguiera species, the bark is covered with small lenticels, and the tree has knee roots.

28. Flowers with white or light orange petals. Calyx lobes extend away from seedling and bend downwards perpendicularly.

Berus Mata Buaya (Bruguiera hainesii)
Berus Mata Buaya (Bruguiera hainesii) - Like other Bruguiera species, the bark is covered with small lenticels, and the tree has knee roots.

29. Calyx ranges from pinkish to bright red. Petals have bristles at the tip.

Tumu Merah (Bruguiera gymnorhiza)
Tumu Merah (Bruguiera gymnorhiza) - Like other Bruguiera species, the bark is covered with small lenticels, and the tree has knee roots.

30. Calyx varies from bright yellow to light green to pinkish. Petals have no bristles or at most 1 or 2 short bristles.

Tumu Putih (Bruguiera sexangula)
Tumu Putih (Bruguiera sexangula) - Like other Bruguiera species, the bark is covered with small lenticels, and the tree has knee roots.



As mentioned, only the 30 true mangrove species are covered in this key. Hopefully I can find time to put up information on the mangrove associates in future :)

Hope this will be useful for other amateur mangrove lovers like me! :P

Monday, November 28, 2011

Nipah Palm (Nypa fruticans)

The Nipah Palm (Nypa fruticans) is a nationally vulnerable mangrove plant from the family Arecaceae. It is one of the most ancient flowering plants and probably the oldest species of palms.

Nipah Palm (Nypa fruticans)
This palm can be seen at most of our major mangrove forests, such as Pulau Tekong, Pulau Ubin, Pasir Ris, Sungei Buloh Wetland Reserve, Mandai, Woodlands Town Garden, Berlayar Creek, Seletar, Lim Chu Kang, Pandan, Kranji, St John's Island and Pulau Semakau, among others.

Nipah Palm (Nypa fruticans)
It generally occurs at the upper reaches of mangrove forests, often forming pure stands, usually on fine-grained substrates. It is often found along tidal waterways as well, especially on sites with high freshwater inputs.

Nipah Palm (Nypa fruticans)
The palm lacks a trunk, but instead, has thick underground rhizomatous forking stems. The stems are sometimes exposed on eroding shores.

Nipah Palm (Nypa fruticans)
It is a monocot, and has huge compound leaves up to 9m long. The long leaflets (60-130cm long) have parallel veins.

Nipah Palm (Nypa fruticans)
The female flower occurs in the form of a spherical head.

Nipah Palm (Nypa fruticans)
The male flowers extend from the main flower stalk below the head of the female flower, but as they mature, the long catkins eventually grow taller than the female flower, somewhat forming a circle surrounding the latter.

Nipah Palm (Nypa fruticans)
The fruiting body is a cluster of brown fruits. The fruits drop off from the stem as they mature, and individual fruits will be dispersed by water.

The seed is edible, and is called "attap chee" in the region. The leaves are used for thatching. A sweet syrup can be extracted from the flower stalk in large quantities and made into palm sugar, or used in the production of alcohol (including ‘toddy’), sugar and vinegar. This palm is hence planted in many areas in the region.

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.
  • Teo, S., Ang, W.F., Lok, A. F. S. L., Kurukulasuriya, B.R. and Tan, H. T. W. (2010) The status and distribution of the nipah palm, Nypa fruticans Wurmb (Arecaceae), in Singapore. Nature in Singapore, 3: 45–52.

Pisang-pisang (Kandelia candel)

The Pisang-pisang Laut (Kandelia candel) is a nationally critically endangered mangrove tree from the family Rhizophoraceae. It occurs at the landward side of mangrove forest or along tidal rivers, usually on sandier substrates, occupying a narrow niche. The last known tree on mainland Singapore died in February 2011. A small population can be found offshore on Pulau Tekong and Pulau Unum.

Pisang-pisang Laut (Kandelia candel)
The flowers are white and occur in clusters, dichotomously branched.

Pisang-pisang Laut (Kandelia candel)

The leaves are narrowly oblong with a rounded tip. The tree has a thickened stem base without proper buttresses or pneumatophores. It has greyish to reddish-brown bark with lenticels for air exchange.

Pisang-pisang Laut (Kandelia candel)
The new leaf buds are laterally compressed and twisted, and are protected by prominent stipules which fall off as the leaves mature.

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 long and green structures seen hanging from the trees are seedlings, and only the brown structures at the top of the green structures are the fruits. The seedling's hypocotyl is narrowly cylindrical with a somewhat pointed tip, growing up to 40 cm long. It is capped by the persistent sepals whose tips bend backwards towards the stalk.

Kandelia obovata
Unfortunately, I do not have pictures of the seedlings of K. candel. What I have above are the seedlings of a closely related species - Kandelia obovata. Previously it was thought that there was only one species of Kandelia - K. candel. Studies published in 2003 showed that there were actually two different species, and the ones growing in the sub-tropical areas north of the South China Sea are renamed K. obovata. The seedlings are similar though.

The wood is used as firewood, making enclosures and stakes. It is also and source of tannin.

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.
  • Sheue, C.-R., H.-Y. Liu & J. W. H. Yong. 2003a. Kandelia obovata (Rhizophoraceae), a new mangrove species from Eastern Asia. Taxon 52: 287- 294.

Buta-buta (Excoecaria agallocha)

The Buta-buta (Excoecaria agallocha) is a common mangrove tree from the family Euphorbiaceae. It is also commonly called "Blind-your-eyes", due to its poisonous sap.

Buta-buta (Excoecaria agallocha)
This mangrove tree can be seen at most, if not all, of our major mangrove forests, such as Pulau Tekong, Pulau Ubin, Pasir Ris, Mandai, Lim Chu Kang, Sungei Buloh Wetland Reserve, Kranji, Khatib Bongsu, Pandan, Woodlands Town Garden and Pulau Semakau, among others.

Buta-buta (Excoecaria agallocha)
It usually occurs on the landward margin of mangrove forests, especially in areas with freshwater inputs. The roots run along the surface of the soil, are often knotted.

Buta-buta (Excoecaria agallocha)
The trunk is greyish or brownish, and somewhat warty. Bark and roots are covered with lenticels for air exchange.

Buta-buta (Excoecaria agallocha)
It has simple, alternate, elliptic leaves with a pointed tip and toothed-margin. Poisonous white latex is present in trunk, stems and leaves, and can cause blistering and (temporary) blindness.

Buta-buta (Excoecaria agallocha)
The tree is deciduous, and leaves turn yellow, orange or even reddish before they are shed.

Buta-buta (Excoecaria agallocha)
The tree bears either male or female flowers. The tiny flowers are spirally arranged on catkin-like, elongated clusters. Male inflorescences are longer (up to 11cm).


Female inflorescences are shorter (up to 4cm long).

Buta-buta (Excoecaria agallocha)
The fruit is a capsule with 3 lobes and compartments, each with 1 seed.

The poisonous sap is used to stun fish. The wood is used for carving, making matchsticks and sulphate-paper pulp. It is not used for firewood due to its unpleasant smoke.

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.

Dungun (Heritiera littoralis)

The Dungun (Heritiera littoralis) is a nationally endangered mangrove tree from the family Malvaceae.

Dungun (Heritiera littoralis)
This tree can be seen at several of our mangrove forests, including Pulau Tekong, Pulau Ubin, Pulau Semakau, Pasir Ris, Sungei Buloh Wetland Reserve, Kranji, Mandai and Lim Chu Kang.

Dungun (Heritiera littoralis)
The tree has a buttressed trunk and dark or grey, fissured bark.

Dungun (Heritiera littoralis)
It has simple, alternate, oblong leaves with silvery undersides, due to the presence of greyish-white scales. The leaves are stiff and leathery.

Dungun (Heritiera littoralis)
The flowers are small, hairy and occur in clusters. There are no petals. Male and female flowers occur on different trees.

Dungun (Heritiera littoralis)
Flowers have a cup-shaped calyx can be reddish or yellowish. Female flowers occur in small clusters, while male flowers are more numerous but smaller in size.


The fruits are woody with a keel on one side, much like boats. They are dispersed by water.

The wood is heavy and very durable, used for making boats, masts and houses. It is also used for firewood and making paper. The bark contains tannin. Fruits and seeds are used to treat diarrhea and dysentery.

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