Sunday, July 15, 2012

Coastal Epiphytes, Ferns & Ground-dwelling Herbs of Singapore

The seashore environment is a very harsh environment for the trees and shrubs growing there. It is usually very dry, due to the land and sea breeze which increases the rate of evaporation. This is more so on rocky and sand shores since the substrates are rather porous. Salt sprays from the sea also have a drying effect on the plants living there. These coastal shrubs and trees, unlike true mangrove plants, are usually found in areas seldom or not inundated such as the back mangroves. Hence, these plants are also called mangrove associates. Many of them can also be found growing in other types of seashore ecosystems, such as sandy or rocky.

In this article, I will share about some of the parasitic plants, epiphytes, ferns and ground-dwelling herbs that I have seen around the coastal areas of Singapore. Note that this guide can only be used in Singapore, as the same species may exhibit a different growth form in other countries.

An epiphyte is a plant that grows upon another plant. Growing on another plant gives the epiphyte better access to sunlight and moisture. A true epiphyte does not derive nutrients from the host plant, unlike parasitic epiphyte which do so. Ferns refer to vascular plants which do not produce seeds but reproduce via spores. In botanical terms, a herb refers to a flowering plant without any persistent woody stem, and the leaves and stem will die down to the soil level at the end of its growing season. Some herbs may have roots or underground stems that grow new shoots for the next growing season, while others die completely and new plants grow from seeds.

This article is divided into the follow sections:

A) True epiphytes (exclude ferns and climbers)
B) Parasitic epiphytes
C) Ferns
D) Ground-dwelling herbs (exclude creepers and grass-like plants)

The species I have included here are definitely not all we have in Singapore - these are just the ones that I have seen. I certainly hope that I can add more species to this page in future.



A) True epiphytes (exclude ferns and climbers)

1. It has a swollen, tuber-like base and opposite leaves.

Baboon's Head (Hydnophytum formicarum)
Baboon's Head (Hydnophytum formicarum) - This epiphyte is critically endangered in Singapore, and got its common name from the swollen stem which resembles a monkey's head. It occurs in mangrove, freshwater swamp and dryland forests. The leaves are leathery and elliptic to broadly lanceolate, oppositely arranged. The small white flowers occur in shallow cup-shaped cavities in thickened nodes on the stem, and the small round or ovoid fruits turn from greenish to orange with maturity. Inside the swollen stem is a labyrinth of tunnels, usually inhabited by ants. It is sometimes planted as an ornamental plant. The stem is used by locals to treat swellings and headache.

2. It is a monocot with green, slightly swollen stems near the base, and fleshy, narrowly oblong-lanceolate leaves.

Pigeon Orchid (Ceraia crumenatum)
Pigeon Orchid (Ceraia crumenatum) - There are several species of epiphytic orchids in the region, but personally I have only seen this species occuring naturally in our mangroves. It bears fragrant white flowers with yellow markings in the middle, and the blooming occurs about 9 days after a sudden drop in temperature, usually due to rain. This common orchid can be found in various forest types, and even on wayside trees in urban areas.

3. It has palmately compound leaves with 4-6 elliptic or somewhat ellilptic leaflets that are not more than 1.5 times as long as broad.

Climbing Umbrella Plant (Schefflera elliptica)
Climbing Umbrella Plant (Schefflera elliptica) - This epiphytic plant occurs either as a straggling shrub or woody climber. I have only seen it growing on mangrove associates in the back mangrove so far, but not on true mangrove trees in Singapore. The flowers occur in clusters with some branches as long as or shorter than the elongated main axis. Each flower is very small. The small fruits usually splitting into 5-6 parts, turning from yellow or orange to black.



B) Parasitic epiphytes

4. It is a mistletoe with elliptic or oblong alternate leaves with glossy upper sides.

Malayan Mistletoe (Dendrophthoe pentandra)
Malayan Mistletoe (Dendrophthoe pentandra) - This common mistletoe grows on various mangrove and coastal shrubs and trees. It also occurs in inland forests. It has small and hairy flowers with very variable colours, ranging from greenish to orange to dark red. The fruits are ovoid and turn red with maturity. They are usually dispersed by birds. The ingested seeds passed through the bird's gut system, and being sticky, they have the tendency to stick to the bird's feathers when it defecates. As the bird rubs against the branches remove the sticky seeds, these seeds will start growing on the branches. This dispersal method is reflected in its name - "mistletoe" is derived from the word "misteltan", and "mistel" is the Anglo-Saxon word for dung, while "tan" means "twig". Hence, "mistletoe" actually means "dung-on-a-twig". Like other mistletoes, the Malayan Mistletoe has special roots (haustoria) which penetrate its host's tissue and draw nutrients from it. A wide variety of animals feed on the leaves, shoots, nectar, flowers and fruits of mistletoes, making them a very important group of plants which can influence the abundance and diversity of animals in the area.

5. It is a mistletoe with ovate opposite leaves with matte upper sides.

Common Chinese Mistletoe (Macrosolen cochinchinensis)
Common Chinese Mistletoe (Macrosolen cochinchinensis) - This common mistletoe grows on various mangrove and coastal shrubs and trees. It also occurs in inland forests. It has small and usually smooth flowers, usually yellow or green but sometimes with reddish markings. The fruits are small, smooth and round, turning from green to yellow and eventually purple with maturity. The glue extracted from the fruit is used to trap birds.

6. It is a mistletoe with obovate or inversely heart-shaped opposite leaves due to a notch at the end. The leaves have matte upper sides.


Pink-flowered Mistletoe (Macrosolen retusus) - Along our shores, this rare mistletoe with pink flowers is only found infesting the Penaga Laut (Calophyllum inophyllum) and Podocarpus (Podocarpus spp.), though further inland it can be found on Salam (Syzygium polyanthum) as well.

7. It is a mistletoe with leathery lanceolate-obovate leaves with more than 3 main veins arranged in a fan-shaped pattern. The stem is green.


Oval-leaved Mistletoe (Viscum ovalifolium) - This uncommon mistletoe grows on various mangrove and coastal shrubs and trees. It also occurs in inland forests. The small flowers are greenish or yellow in colour, while the small round fruits range from yellowish-green to brownish to red.



C) Ferns

8. It is a fern with its fronds divided into 2 main dichotomous lobes which are further divided into numerous unequal lobes.

Bua Cek (Dipteris conjugata)
Bua Cek (Dipteris conjugata) - In Singapore, this critically endangered fern is usually found growing on cliff faces in coastal areas. Younger plants have fewer but more rounded lobes. In the region, they can be found growing in mountain clearings at much higher altitudes. It is sometimes planted as an ornamental plant. The roots are believed to have some traditional medicinal uses in the region.

9. It is a fern with a rosette of long and leathery leaf blades at the top.

Bird's-nest Fern (Asplenium nidus)
Bird's-nest Fern (Asplenium nidus) - This common epiphytic fern got its common name from its resemblance to bird's nest (with some imagination). It can be seen growing on trees in our forests and in urban areas. The spores are held in narrow strips (sori) on the undersides of the fronds. The rosette of leaves traps dead leaves, resulting in a spongy humus that traps rain water. This rain water is also used by other epiphytes growing nearby. It is commonly planted as an ornamental plant.

10. It is a fern with 2 distinct types of fronds - erect fan-like fronds and drooping antler-like fronds.

Staghorn Fern (Platycerium coronarium)
Staghorn Fern (Platycerium coronarium) - This epiphytic fern is common grown as an ornamental plant on wayside trees. It can also be found occuring naturally in our forests. The dangling fertile leaves are divided dichotomously, growing up to 2m long or more, with the spores on shortly stalked, semi-circular to deeply heart-shaped lobes. The erect fan-like fronds trap dead leaves and moisture, providing nutrients for the plant itself and other epiphtyes that may be growing on it.

11. It is a fern with 2 distinct types of fronds - the smaller oak leaf-like nest fronds, and long fertile fronds with numerous blade-like lobes on both sides (feather-like shape).

Oak Leaf Ferns (Drynaria spp.)
Oak Leaf Ferns (Drynaria spp.) - Two species of very similar Oak Leaf Ferns are recorded from Singapore - Drynaria quercifolia and Drynaria sparsisora. I am unable to differentiate them as yet. Oak Leaf Ferns are commonly seen growing on trees in our forests and roadsides. The long foliage leaves are usually stiff and leathery. The sori are small and numerous, occuring in irregular rows at the junction of the veins. The roots are used to treat eye infection. It is also planted for ornamental purposes.

12. It is a fern with many of its fronds deeply lobed on both sides of the midrib, resulting in several pointed tips.

Paku Wanggi (Phymatosorus scolopendria)
Paku Wanggi (Phymatosorus scolopendria) - This epiphytic fern is fairly common in Singapore, occuring in the forests and roadsides as well. It has a greenish, creeping rhizome with dark brown scales. The sori occur in one to three irregular rows on either side of the midrib, extending onto the lobes. The leaves contain a fragrance, coumarin, that can be used to scent clothes and coconut oil. The rhizome is used by locals to treat gecko bites and to accelerate childbirth.

13. It is a fern with narrow and long, glossy fronds, with a midrib that is grooved above and strongly raised below.

Pyrrosia longifolia
Pyrrosia longifolia - This common epiphytic fern also occurs in various forest types and on roadside trees. It has long, creeping rhizomes and leathery leaves with a smooth surface, while the lower surface is covered with greyish, star-shaped hairs. The small and round sori cover the lower surface of the leaves in the upper part in irregular rows between the midrib and the leaf edge. This plant is used by locals to ease labour pain during childbirth.

14. It is a fern with elongated lanceolate fronds that are gradually tapered towards both the base and tip. The midrib is distinct on the upper surface, but usually less distinct on the lower surface.

Tape Fern (Vittaria elongata)
Tape Fern (Vittaria elongata) - This common epiphytic fern occurs in lowland forests, including mangrove, and may even grow on rocks, especially those in shaded areas. The sori are found in a deep groove near he margin, which somewhat curl towards the lower surface at maturity. It is sometimes planted for ornamental purposes.

15. It is a fern with round and fleshy scale-like leaves sterile leaves and longer, ribbon-like fertile leaves.

Dragon's Scale Fern (Pyrrosia piloselloides)
Dragon's Scale Fern (Pyrrosia piloselloides) - This fern is commonly found growing on trees in parks, roadsides and forests. The sori are arranged in a broad band along the edge of the leaf. This plant is used by locals to treat rashes and headaches.

16. It is a fern with somewhat triangular compound leaves and hairy rhizomes.

Rabbit's Foot Fern (Davallia divaricata)
Rabbit's Foot Fern (Davallia divaricata) - This epiphytic fern is very common in Singapore, and is found growing on trees in various habitats. It got its common name from the hairy rhizome, which resembles a rabbit's foot with some imagination. The lobes of sterile leaflets are elliptic and entire, at most slightly serrated, while the lobes of fertile leaflets are elliptic-oblong, deeply lobed with jagged edges. The sori occur on the tip of each vein.

17. It is a fern with reddish new fronds. Sterile compound leaves have green, smooth and glossy elliptic leaflets, while fertile fronds have narrowly linear leaflets covered with sporangia on the undersides.

Paku midung (Stenochlaena palustris)
Paku Midung (Stenochlaena palustris) - This ground fern can form extensive cover over the ground or climb up trees. It is commonly found in open areas where there is enough moisture. It also commonly occurs as a climber in the forest. The stem can be made into a durable rope, and young leaves are eaten as a vegetable.



D) Ground-dwelling herbs (exclude creepers and grass-like plants)

18. It has spirally arranged leaves.

Crinum Lily (Crinum asiaticum)
Crinum Lily (Crinum asiaticum) - This nationally critically endangered coastal plant in Singapore has its lanceolate leaves spirally arranged. It has an fleshy underground bulb, and bear white flowers (sometimes with a purplish edge) with purple stamens. The fruits are round and white. Naturally-occuring ones are sometimes found in shaded areas on our shores, though NParks has also replanted many of them in various coastal areas. It is also sometimes planted as an ornamental plant. Traditionally, this poisonous plant is used as a purgative and for treating foot sores.

19. It has palmately or pinnately lobed leaves.

Seashore Bat Lily (Tacca leontopetaloides)
Seashore Bat Lily (Tacca leontopetaloides) - This nationally critically endangered plant is sometimes seen growing in sandy areas at the back mangrove or supralittoral zone of beaches of some of our southern islands. The flowers are greenish, borne on tall stalks with greenish bracts at the top, while the fruits are green and round. Seeds are small and oblong, with several ridges running along the length. This plant is usually dormant for part of the year, and the leaves will dry up. After a few months, new leaves will grow from the round underground tuber. The tubers can be used to make flour, which in turn can be made into a variety of puddings for consumption.

20. It is a shrubby herb and the edges of its alternate leaves are serrated.

Indian Camphorweed (Pluchea indica)
Indian Camphorweed (Pluchea indica) - This shrubby herb occurs at open areas along the coast or back mangroves. It has light purple or whitish composite flowers. The dried fruits are light with tufts of white hair, and are dispersed by wind. The plant contains compounds found to be anti-diabetics, and neutralises the venom of some snakes.

21. It appears shrubby with opposite leaves. Some have spines on the leaves, while others may not.

Sea Holly (Acanthus spp.)
Sea Holly (Acanthus spp.) - Singapore has 3 species of Sea Hollies (Acanthus spp.) in our mangrove forests - Acanthus volubilis, Acanthus ebracteatus and Acanthus ilicifolius. Acanthus volubilis occurs as a bush-like, sprawling herb, or when there are other taller structures around, as a climber. There are no spines on its leaves. The other two species occur as low, sprawling herbs and seldom climb. The leaves in areas exposed to the sun tend to have more spines than the shaded ones, which may even be spineless. More information here.



References
  • Chong, K. Y., H. T. W. Tan and 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 and 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.
  • Lok, A. F. S. L., W. F. Ang and H. T. W. Tan, 2009. The status and distribution in Singapore of Dipteris conjugata Reinw. (Dipteridaceae). Nature in Singapore, 2: 339-345.
  • Ng, P. K. L. and N. Sivasothi. 1999. A guide to the mangroves of Singapore 1 : the ecosystem and plant diversity. Singapore Science Centre. Singapore. 168 pp.

4 comments:

Reuben Lim said...

Great guide!

Ron Yeo said...

Thanks Reuben!

Bernard Bate said...

Thank you, very helpful.

Richard Lane said...

Excellent guide and photos. Really useful for a visiting naturalist.