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Flora Singapore

The goal of Flora Singapura is to bridge the gap between the terse technical descriptions of plants found in the various botanical text books and what we observe in the (Singapore) forests. I approach this by using photographs and commentary to illustrate and describe the identifying field characters of the trees and shrubs that from time to time command my attention. There are some 2000 species of native vascular plants in Singapore and so far I have only a modest number of species illustrated, I will add to the content as often as I can.

Be Creative – Plant Native

Lauraceae (Laurel) Family

The Laurels are a large family represented in Singapore by some 40 species in 12 Genus. Some areas of secondary forest in our Nature Reserves are dominated by Laurels.

Actinodaphne Genus
 
Trees of this genus have leaves arranged in whorls along the stem with long intervals between the leaf nodes.

Cinnamomum Genus

Cinnamon is a well known product from trees of thus genus and the trees are also used for ornamental purposes. In Singapore there are three native species one of them C. inners is considered very common, the other two species less so.

Dipterocarpaceae Family

Dipterocarpaceae is the defining family for our South East Asian Dipterocarp forests and the trees of this family are large, commercially valuable and dominate the forest as many are emergent species standing above the canopy of surrounding forest. The life and times of Dipertocarps also makes for an interesting story, from their method of fruiting to Seed dispersal and how they came to be distributed across Africa and Asian continents to the high level of diversification in South East Asia.
Dipterocarp seed dispersal involves a winged nut falling from the mother tree, with the only lateral movement made possible by whatever prevailing breeze is available beneath the canopy. At best these seeds will fall obliquely perhaps one or two crown widths during fruiting on a windy day.  It is also known that

the fruits of Dipterocarpaceae are generally intolerant of salt water and because of this, sea boundaries are a major obstacle to dispersal.  If you consider this mind numbingly slow linear rate of dispersal plus the time it takes for  a seedling to become a mature reproductive tree you may realize that there is no way this family could have the breadth of distribution it enjoys simply through terrestrial seed dispersal. Scientific studies have identified correlations between distribution and diversification of Dipterocarp species with tectonic plate movements and the currently accepted theory of distribution involves the family originating in Africa and deploying to South East Asia via these plate movements.

The family is considered to have its origins in Gondwanaland (the great southern continent) and crossed onto the Asian continent  during he Tertiary period. The animation shown on the left is one of many that are available from the United States Geological Survey that address the subject of historical plate movements.  This particular animation follows the African continent and the Indian sub-continent can be seen breaking away and moving north-east towards its current location.
More recently (in the past 11,000 years) and more locally, the Sumatra, Malay Peninsular and Borneo land masses were part of one single land mass with a major river valley separating east and west portions. It is apparent from the current distribution of Dipterocarps in the South East Asian region that extensive regional speciation occurred within this extensive system.
Interestingly South East Asia can be shown (see map below) to be the centre of diversification for Dipterocarpaceae and this is attributed to the favourable bio-geographical conditions that prevail here, e.g. the absence of annual drought resulting in high survival rates for seedlings, supra-annual flowering and mast fruiting which overwhelms the seed predators to the extent that there are sufficient remaining seeds after the predators have become fat to achieve a higher rate of successful germination compared to that which could be achieved if fruiting occurred independently.

Myrtaceae (Myrtle) Family

The Myrtle family is very well known for the  Eucalyptus (Gum Trees) and Melaleuca (Paper Bark) species of Australia, in Singapore the family is very nicely represented by the Syzygium genus which at last count includes some 50 native species, a number of which are cultivated as road-side trees.  This family also includes the ubiquitous Rhodamnia cinarea which is a very common species in secondary forest.

Syzygium Genus

Most of the Syzygium species were previously categorized under the Eugenia genus and as a result of this reorganization the species names have been changed slightly, for example Eugenia grandis is now known as Syzygium grande and Eugenia polyantha is now known as Syzygium polyanthum. The reason for these changes is that the gender of the latin names has been made consistent. Therefore when quoting botanical names for this genus, extra care must be exercised with respect to spelling, it is very easy to revert to the old Eugenia species names and mix them up with the Syzygium genus name. Anybody caught mixing up the old species names will be severely punished.
Myristicaceae family is represented in our Singapore forests by 5 genera: EndocomiaGymnacrantheraHorsfieldiaKnema
and Myristica representing some 31 species. The trees are monopodal particularly when young though some lose this trait as they mature, have alternate arranged leaves and pink or red exudate.
The fruits are generally round to egg shaped and members of this family are fairly easy to recognize when fruiting.  In the absence of fruits (or flowers), the monopodal stem with wagon wheel branching is the important visual clue to recognizing a nutmeg tree.
The fruits of Nutmegs can be fairly large and the dihescent capsules will usually open in the tree offering the brightly coloured arilate seeds as enticement to the birds. The primary seed dispersal agents are larger birds with robust beaks such as pigeons and Hornbills which are known as primary seed dispersers for the nutmeg family.
The near extinction of Hornbills in Singapore has been cause for concern for the Nutmegs, with seed dispersal being left up to the secondary dispersal agents – the rodents (squirrels and rats).
Most of the Nutmeg species illustrated here have been provisionally identified mainly from vegetative characters. As fertile specimens are encountered some alterations may be required.
Gymnacranthera Genus
The main identifying characters of this genus are secondary veins looped well clear of the margin and quite prominent on the underside of the leaf which is pale compared to top side. On the top side of the leaf, the midrib is sunken and this is a good distinguishing character for the genus.

Apocynaceae (Periwinkle) Family

The Apocynaceae family is characterized by having copious amounts of white latex in most parts of the plant, usually whorled leaves and twinned seedpods. The flowers are typically 5-petaled and propeller like with each petal overlapping one adjacent petal and itself being overlapped by the next adjacent petal. Once familiar with some of the common members of this family you would have difficulty moving about in Singapore and not recognizing them. As common as many of the species of this family are, some are critically endangered in Singapore due to their special habitat needs.

Forest Habitats

Despite being extensively developed there remains in Singapore small examples of most of the original forest habitats that covered the island up till the arrival of Sir Stamford Raffles. The small fragments of original forest may be found in the various Nature Reserves and Nature Parks of Singapore and include Primary Dipterocarp Forest, Secondary Forest, Fresh Water Swamp Forest, Coastal Forest and Mangrove Forest.

Tree Falls

The Central Catchment Nature Reserve consists of many fragmented sections of forest growing on peninsulars that extend into the water storage reservoirs making them vulnerable to strong gusts of wind generated during storm events. Almost every year some section of the forest is blown over due to strong wind gusts generated by Sumatran Squals or other more localized weather events.
The most recent tree fall occurred on 11 Feb 2011 in the vicinity of Mandai Rd (picture above). This particular tree fall attracted much public attention as it was the first to occur in a location that could be seen by the general public and was subsequently reported on in the local news papers.

In this case some 40 hectares of mature secondary forest was literally flattened by a local storm which passed over the Upper Seletar Reservoir. Much of the forest damage seems to have occurred around the water inlets and it seems likely that winds passing unrestricted over the reservoir surface were funneled into these inlets and accelerated as the inlets narrowed.

Similar patterns of wind damaged forest concentrated about reservoir inlets were observed after a line of Sumatran Squals  passed over Singapore in early  September 2010. This tree fall was less extensive and occurred in secondary forest adjoining the Upper Peirce Reservoir in the vicinity of Chestnut Avenue.
It is expected surviving saplings, dormant seed stock and opportunistic pioneer species will soon naturally regenerate these tree-fall areas.

Botanical Recipes

I always find traditional uses for plants an interesting subject. There are books that cover this subject and sometimes I find it amusing that the Chinese will use a plant for one thing, while the Malays will use it for something completely different.   My own experience with traditional uses of local forest product is a bit closer to home, my cooking pot actually. In this section I will document various recipes that involve the local flora. All the botanical materials used in these recipes have either been “borrowed” from road side trees or acquired at local markets and never taken from Nature Reserves.