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Alstonia spatulata


Alstonia spatulata Blume

Family Name: Apocynaceae
Synonyms: Alstonia cochinchensis, Alstonia cuneata
Common Name: Marsh Pulai, Hard Milkwood, Siamese Balsa, Pulai Basong, Basong, Pokok Rejang, Pulai Paya, Pulai Putih

Alstonia spatulata or Marsh Pulai is a native tree of Singapore, measuring between 10 - 25 m tall. It has spoon to drop-shaped leaves, light yellow, cream to white fragrant flowers and petals with a wavy margin. Given its tolerance to waterlogging, Marsh Pulai is selected to grow along urban canals, pond edge plantings, areas in parks and gardens that are waterlogged.


Family Name
Genus Epithet
Species Epithet
Name Authority
Name Status (botanical)
Common Names
Species Summary

Classifications and Characteristics

Plant Division Angiosperms (Flowering Seed Plants) (Dicotyledon)
Plant Growth Form Tree (Medium (16m-30m))
Lifespan (in Singapore) Perennial
Mode of Nutrition Autotrophic
Maximum Height 25 m


Native Distribution Myanmar, Indochina, Thailand, Malaysia, Singapore, Indonesia, Borneo, to New Guinea
Native Habitat Terrestrial (Riverine, Primary Rainforest, Secondary Rainforest, Freshwater Swamp Forest)
Preferred Climate Zone Tropical
Local Conservation Status Native to Singapore (Endangered (EN))

Description and Ethnobotany

Growth Form Alstonia spatulata is a small to large tree, 10- 25 m tall, forming symmetrical  buttresses to 1.2m high
Trunk The bark of the Marsh Pulai is a pale - dark grey to almost black, smooth, scaly or  very slightly fissured, peeling off in square/ rectangular flakes, 
Foliage The leaves of Alstonia spatulata are arranged in whorls of 3-5, without distinct intrapetiolar stipule at the base of the leaf stalk; leaf stalks short, slightly winged, 4-15mm in length.  Leaf blades papery to the touch (coriaceous), spatulate (spoon shape) to obovate (drop shape) that are 3-12 by 1.8-4.8 cm, apex of leaves rounded, sometimes retuse. Upper surface of leaves glossy green, under surface pale green. Leaves with 20-40 pairs of lateral veins that are closely spaced and almost perpendicular to the mid rib. Leaf stalks slightly winged. 
Flowers Inflorescence 3-11cm long, with 3-6 fragrant, white to light yellow to cream colored flowers arranged in a loose cluster. Calyx glabrous; Cororlla glabrous (without hairs) on the outside, corolla lobes with undulate (wavy) margins, spreading or almost reflexed in the open flower
Fruit Its fruits are long, slender follicles, borne in pairs, 12-25 cm long by 2.5-3 mm wide, containing numerous seeds.
Habitat It grows in swamp forests, mostly in secondary vegetation, on sandy soils up to 600 m altitude.
Similar Similar to Alstonia pneumatophora in leaf shape, size and venation, but can be immediately told apart from A. pneumatophora as Alstonia spatulata does not have pneumatophore roots (knee like breathing roots). It also differs from A. pneumatophora  in the number of pairs of secondary veins on the leaves (18-30 pairs in A. pneumatophora compared to 20-40 pairs in A. spatulata), having a glabrous calyx , and the glabrous fruits. 
Associated Fauna The fragrant flowers are insect pollinated. It is also the food plant for caterpillars of the moth Parotis marginata.
Cultivation Alstonia spatulata can be propagated by seeds.
Ethnobotanical Uses Medicinal: Traditional Medicinal Uses
In Southeast Asia countries like Indonesia, the plant is used in traditional medicine to treat toothaches <1>, diabetics, sores and skin diseases <2>.

It is important to note that some therapeutic effects from traditional medicinal uses of plants are not currently supported or verified by scientific research. As all Apocynaceae species, Alstonia angustiloba contain white, milky sap which can cause allergic reactions especially for those with sensitive skins. Medical advice should be sought before use.  
Timber & Products: The lightweight trunk wood of Alstonia spatulata is commonly used for household items, carvings, floats, and plywood. The plywood is used for coffins in Peninsular Malaysia, and for floats for nets in Thailand, and Sumatra. Pith helmets were manufactured from the wood of the roots. The lightweight root wood is also used as a cork substitute.
Cut - Dried Flower: The fragrant flowers of the Marsh Pulai are used in garlands.

Landscaping Features

Landscaping It is suitable for growing in urban canals, pond edge plantings, in waterlogged areas in parks and gardens as it withstands and stabilises waterlogged soils.
Desirable Plant Features Ornamental Flowers, Fragrant
Landscape Uses General, Parks & Gardens, Riverine, Pond / Lake / River, Marsh / Bog
Thematic Landscaping Naturalistic Garden, Water Garden, Marsh Garden, Fragrant / Aromatherapy Garden

Fauna, Pollination and Dispersal

Pollination Method(s) Biotic (Fauna)
Seed or Spore Dispersal Abiotic

Plant Care and Propagation

Light Preference Full Sun
Water Preference Moderate Water, Lots of Water
Plant Growth Rate Moderate
Rootzone Tolerance Waterlogged Soils (Drains Site, Does not Drain Site)


Foliage Retention Evergreen
Mature Foliage Colour(s) Green
Mature Foliage Texture(s) Leathery
Foliar Type Simple / Unifoliate
Foliar Arrangement Along Stem Whorled
Foliar Attachment to Stem Petiolate
Foliar Shape(s) Non-Palm Foliage (Obovate)
Foliar Margin Entire
Foliar Apex - Tip Rounded
Foliar Base Cuneate
Leaf Area Index (LAI) for Green Plot Ratio 3.0 (Tree - Intermediate Canopy)

Non - Foliar and Storage

Trunk Type (Non Palm) Woody
Stem Type & Modification Woody
Root Type Underground (Tap Root, Fibrous Root)

Floral (Angiosperm)

Flower & Plant Sexuality Bisexual Flowers
Flower Colour(s) White
Flower Grouping Cluster / Inflorescence
Flower Symmetry Radial

Fruit, Seed and Spore

Mature Fruit Colour(s) Brown
Fruit Classification Simple Fruit
Fruit Type Dehiscent Dry Fruit , Follicle


References <1> Diba, F., Yusro, F., Mariani, Y. & Ohtani, K. (2013). Inventory and biodiversity of medicinal plants from tropical forest based on traditional knowledge by ethnic Dayaknese communities in West Kalimantan Indoneisa. Kuroshio Science 7(1): 75-80.

<2> Plant Resource Of Southeast Asia (continuously updated). Alstonia spatulata (PROSEA) - PlantUse. Accessed 19 October 2023. 

Image Repository



Master ID 1413
Species ID 2706
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: 19 October 2023.