Lee Kong Chian Natural History Museum

Dyera costulata (Miq.) Hook.f.

Kingdom:Plantae
Phylum/Division:Magnoliophyta
Class:Eudicots
Order:Gentianales
Family:Apocynaceae
Genus:Dyera
Species:D. costulata
Common Names:Jelutong
Status:Common

Description

The Jelutong is a huge tree that can grow to 60 m or more in the forest, but will grow to about 30 m in parks and gardens. It has dark grey bark that can appear black when it is wet on rainy days. Branching takes place in whorls with ascending layers. The leaves also grow in whorls of 6–8; are ovate-oblong and 7–18 cm long. Flowers are small (about 2 mm). Fruits are in pairs of massive woody pods about 20–30 cm long and are curved almost vertically upwards like a pair of horns. When fruits are ripe, the woody pods will split along one side, releasing large, flat and winged seeds.

Read more about the Gentianales order.
Read more about the Apocynaceae family.

Localities

Bukit Timah Nature Reserve, MacRitchie, Singapore Botanic Gardens Jungle

General Biology

Jelutong changes its leaves during the dry season. During short dry spells, they may change leaves on just certain branches but during longer dry spells, the whole crown may loose their leaves at once and begin growing again. The flowers are nocturnal, opening between 5–7pm and fall off the next morning at about 5–7am. The flowering lasts about 10 days. Fruits take 2–3 months to ripen. Generally all the trees of a district change their leaves and flowers simultaneously, but there are exceptions.

Human Uses

Jelutong was previously valued for its latex to be used as rubber. It is preferred for rubber materials that did not require elasticity. The sap is also used as a base in chewing gum and is known to contain compounds with anti-allergic effects. Jelutong is also known for its lightwood that is easy to work with. The timber has been used for making things like pencils, photoframes and wooden handicrafts.

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.

Corlett, R.T., 2011. Jelutong Dyera costulata. Pp. 352. In: Ng, P.K.L., R.T. Corlett & H.T.W. Tan (editors), Singapore Biodiversity. An encyclopedia of the natural environment and sustainable development, Editions Didier Millet, Singapore, 552 pp.

Corner, E.J.H., 1988. Wayside trees of Malaya. Third edition. Volumes 1-2. Malayan Nature Society, Kuala Lumpur. 861 pp.

Keng, H., 1990. The Concise Flora of Singapore: Gymnosperms and Dicotyledons. Singapore University Press, Singapore. 222 pp.

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