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Shorea sumatrana (Slooten ex Thorenaar) Desch

Family Name: Dipterocarpaceae
Synonyms: Isoptera sumatrana Slooten ex Thorenaar, Isoptera borneensis auct. non Scheff. ex Burck: King & Gamble
 
Common Name: Sengkawang, Balau Sengkawang Air, Kedawang

Shorea sumatrana, also known as Sengkawang is a critically endangered tree in Singapore. Growing up to 30 m tall, it has woody fruit, each with five orbicular calyx lobes. It produces Balau timber, a heavy hardwood that is prized regionally for heavy construction.

Full Sun: 6-8h Moderate Water Native to Singapore Tree

Name

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Genus Epithet
Species Epithet
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Species Summary

Classifications and Characteristics

Plant Division Angiosperms (Flowering Seed Plants)
Plant Growth Form Tree
Lifespan (in Singapore) Perennial
Mode of Nutrition Autotrophic
Plant Shape Broad / Mushroom / Hemispherical
Maximum Height 30 m

Biogeography

Native Distribution Thailand, Peninsular Malaysia, Singapore and Sumatra
Native Habitat Terrestrial
Preferred Climate Zone Tropical
Local Conservation Status Native to Singapore (Critically Endangered (CR))

Description and Ethnobotany

Growth Form It is a tree, up to 30 m tall with buttresses. Bark is smooth with many lenticels when young, and gradually becoming scaly with age. Stipule is lanceolate (7 mm long) and falls off early.
Foliage Leaves are green, papery to thinly leathery and arranged alternately. Each leaf is elliptic to ovate shaped (7 – 14 cm long and 4 – 7 cm wide). The leaf base is blunt to wedge shaped while leaf tip is tapering (0.6 – 1.2 cm long). The upper surface of the leaf is glabrous while the lower surface is scaly (lepidote) or glabrous. Each leaf has 9 – 12 pairs of secondary veins. Both the midrib and secondary veins are sunken above and visible and prominent below. The petiole is slender (1.1 – 1.7 cm long) and sparsely covered with soft hairs.
Flowers Flowers occur in a cluster as a panicle inflorescence at the terminal or axillary position. Inflorescence is single-branched, reaching up to 10 cm long, and comprises of up to 6 flowers. All the flowers on the branch on to the same direction (secund). Flower is small, creamy white to pale yellow with pink tinge at base of the petal. The petals are glabrous on the inside while hairy on the outside. Each flower has 22 – 27 stamens with oblong anthers tipped by bristly appendages slightly shorter than anther. The ovary is densely hairy, conical to hourglass-shaped with short smooth style.
Fruits The fruit is woody and covered with soft hairs. Each fruit has 5 orbicular calyx lobes (0-8 – 1.1 cm long and 0.9 – 1.2 cm wide). These calyx lobes are almost equal sized. The orbicular calyx lobe is a key feature to identify Shorea sumatrana. The nut is globose (1.1 – 1.4 cm diameter) with a short tip.
Habitat It is found in swamp forests, and lowland dipterocarp forest, near river bank.
Similar Shorea seminis is very similar to Shorea sumatrana. S. seminis occurs from Borneo and the Philippines, while Shorea sumatrana occurs in Thailand, Peninsular Malaysia, Singapore and Sumatra.
Associated Fauna Flowers are pollinated by insects.
Cultivation It can be propagated by seed.
Etymology Latin Shorea, commemorating Sir John Shore (1793-1798), the Governor-General for the British East India Company; Latin sumatrana, refers to Sumatra, one of the places where it occurs naturally.
Ethnobotanical Uses Timber & Products ( it produces Balau timber, a heavy hardwood that is prized regionally for heavy construction, such as bridges, railway sleepers, powerline posts, wagons and fence posts. )
[Others]: One mature individual was found in Singapore Botanic Gardens’ Jungle and estimated to be 167 years old.

Landscaping Features

Plant & Rootzone Preference - Tolerance Well-Drained Soils, Moist Soils
Landscape Uses Reforestation, Parks & Gardens

Plant Care and Propagation

Light Preference Full Sun
Water Preference Moderate Water
Plant Growth Rate Slow

Foliar

Foliage Retention Evergreen
Mature Foliage Colour(s) Green
Mature Foliage Texture(s) Leathery, Papery
Foliar Type Simple / Unifoliate
Foliar Arrangement Along Stem Alternate
Foliar Attachment to Stem Petiolate
Foliar Shape(s) Non-Palm Foliage (Elliptical, Ovate)
Foliar Venation Pinnate / Net
Foliar Margin Entire
Foliar Apex - Tip Acuminate
Foliar Base Rounded / Obtuse, Cuneate
Leaf Area Index (LAI) for Green Plot Ratio 2.5 (Tree - Open Canopy)

Non - Foliar and Storage

Trunk Type (Non Palm) Woody
Mature Bark Texture Scaly
Stem Type & Modification Woody
Root Type Underground

Floral (Angiosperm)

Flower & Plant Sexuality 1 Bisexual Flowers
Flower & Plant Sexuality 2 Bisexual Flowers
Flower Colour(s) Cream / Off-White
Flower Grouping Cluster / Inflorescence
Flower Location Axillary, Terminal
Flower Symmetry Radial
Individual Flower Shape Saucer-shaped
Inflorescence Type Panicle
Flowering Period Every Few Years
Flowering Habit Polycarpic

Fruit, Seed and Spore

Mature Fruit Colour(s) - Angiosperms and Gymnosperms Brown
Mature Fruit Texture(s) Hairy / Hirsute
Fruit Classification Simple Fruit
Fruit Type 1 Indehiscent Dry Fruit
Fruit Type 2 Nut / Nutlet
Seed Quantity Per Fruit Few (1-5)

References

References Ashton, P.S. (1982). Dipterocarpaceae. In: van Steenis, C.G.G.J. (ed.) Flora Malesiana, ser.1, vol. 9, part 2, pp. 237–552, 575–600. The Hague/Boston/London: Martinus Nijhoff/Dr. W. Junk Publishers.
Ganesan, S.K. & Ali Ibrahim (2018). Shorea sumatrana (Dipterocarpaceae), a remarkable new addition to the flora of Singapore. Gardens’ Bulletin Singapore 70: 261–266.
Pooma, R., Poopath, M. & Newman, M.F. (2017). Dipterocarpaceae. In: Santisuk, T. & Balsev, H. (eds) Flora of Thailand, vol. 13, part 4, pp. 557–685. Bangkok: The Forest Herbarium, Royal Forest Department.
 

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Master ID 1835
Species ID 3128
Flora Disclaimer The information in this website has been compiled from reliable sources, such as reference works on medicinal plants. It is not a substitute for medical advice or treatment and NParks does not purport to provide any medical advice. Readers should always consult his/her physician before using or consuming a plant for medicinal purposes.
Species record last updated on: 16 November 2021.
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