Baccaurea motleyana

Rambai (Baccaurea motleyana)
Scientific name	Baccaurea motleyana
Common names	Rambai; mafai-farang; rambi
Genus	Baccaurea
Family	Phyllanthaceae
Order	Malpighiales
Growth form	Evergreen tree, usually smaller than its maximum size
Native range	Thailand, Malaya, Sumatra, and Borneo; wet tropical biome
Mature size	About 15 to 25 m in larger trees; often smaller in cultivation
Climate and site	Hot, humid lowland tropics; rainforest or riparian settings
Soil	Moist, well-drained alluvial or other suitable tropical soil; reported pH 5 to 6
Propagation	Fresh seed; air-layering of female trees; budding or grafting
Years to fruit	N/A
Fruit	Buff-colored, 2 to 4 cm fruit in racemes from branches and sometimes trunk
Harvest	Thailand report: generally July to August; regional timing varies

Rambai (Baccaurea motleyana) is a Southeast Asian fruit tree in the family Phyllanthaceae. Kew places its native range in Thailand, Malaya, Sumatra, and Borneo and associates it with the wet tropical biome.^[1] The fruit is borne in conspicuous racemes on older branches and, in some trees, on the trunk. It is eaten fresh and is also used for drinks and pickles.^[2]

Description

Rambai tree with abundant fruit borne on branches and trunk.

Rambai is an evergreen tree with a dense crown. Larger trees are reported at about 15 to 25 m, although cultivated trees may be smaller. FAO describes velvety twigs, petioles, and lower leaf surfaces, with obovate-lanceolate to elliptical leaves about 20 to 35 cm long.^[2]

The species is dioecious in the Thai horticultural account, with separate male and female trees. The inflorescences are ramiflorous. Female racemes may be 25 to 60 cm long, and fruit occur in communal strings from twigs and main branches and, to a lesser extent, the upper trunk.^[2]

The fruit is generally buff-colored, smooth to thinly puberulous, and about 2 to 4 cm in diameter. The translucent white pulp surrounds a variable number of seeds and may range from acid to sweet and palatable among trees and selections.^[2]

Growing

Rambai is a hot, humid lowland-tropical tree of primary and secondary rainforest and occasional riparian forest. Useful Tropical Plants reports cultivation from low elevations and a preference for warm conditions; Kew's biome data supports treating it as a wet-tropical plant rather than a dry-site fruit tree.^[1][3]

Soil

In its reported habitat, rambai occurs in wet tropical forest and sometimes near rivers. Secondary horticultural guidance describes alluvial soils where water is available and successful growth on yellow clay, sand, and limestone, provided the soil remains moist but drains. A pH around 5 to 6 is reported as preferred, with a broader tolerance of roughly 4.5 to 6.5.^[3]

For cultivation, aim for moisture-retentive but aerated soil rather than a permanently stagnant root zone. The available sources do not establish a species-specific flooding duration, so prolonged anaerobic saturation should not be presented as harmless.

Sun and humidity

Useful Tropical Plants reports full sun or light shade. The natural setting is humid lowland forest, but dense humidity should be paired with airflow. Young container plants can be acclimated to brighter exposure gradually; mature trees require enough light for a dense crown and fruiting wood.^[3]

Seasonal changes

There is no single region-wide rambai calendar. FAO reports a general July to August fruit season for Thailand; other parts of the range have different rainfall patterns and harvest dates.^[2] Keep root moisture more consistent during active growth and fruit development, and do not impose a dry-climate irrigation schedule on a wet-tropical species. Species-specific dormancy and cold-response data are N/A.

Propagation

Fresh seed is reported to germinate in a few days, but seedlings do not guarantee a fruiting female tree. Because the Thai account describes separate male and female trees, air-layering a known female is the more direct way to preserve fruiting sex and fruit quality. Budding and grafting onto rambai rootstocks are also reported.^[2][3]

Species-specific years to fruit were not established in the sources consulted; the summary field is therefore retained as N/A rather than filled from related Baccaurea species.

Flowering, fruiting, and harvest

Rambai fruits develop in racemes on older wood, branches, and sometimes the trunk. Trees may carry green and buff-colored fruit at the same time as different fruits mature. The Thai report gives July to August as a general season, but local rainfall, tree sex, selection, and site can shift flowering and harvest.^[2]

Harvest the fruit when fully colored and ripe. The pulp varies from acid to sweet among trees. Choose sweet, palatable clones for propagation when a fruiting selection is available; the FAO account identifies selection and clonal propagation as the practical route for preserving desirable fruit quality.^[2]

Fruit and uses

Ripe rambai is eaten fresh. The pulp can be crushed for a drink, sweetened and diluted, or pickled for use with curries. The fruit is small and seed-bearing, and the pulp commonly adheres to the seed. The FAO account notes that very large fresh consumption can upset the stomach in its Thai context, so ordinary food use should not be generalized into a medicinal claim.^[2]

Photos

Heavy rambai fruiting throughout the canopy at the MARDI rare fruit genebank in Serdang, Selangor, Malaysia.

Young rambai fruit hanging on the tree.

References

• Kew, Plants of the World Online: Baccaurea motleyana, accessed 2026-08-24.
• Suranant Subhadrabandhu, Under-Utilized Tropical Fruits of Thailand, FAO RAP Publication 2001/26, section 6 “Mafai-farang (Baccaurea motleyana)”, accessed 2026-08-24.
• Useful Tropical Plants: Baccaurea motleyana, accessed 2026-08-24.

Image credits

• Fruits of Baccaurea motleyana (Phyllanthaceae).JPG — NusHub, CC BY-SA 3.0; cut-open rambai fruit showing pulp and seeds.
• Tree of Baccaurea motleyana (Phyllanthaceae).JPG — NusHub, CC BY-SA 3.0; tree with fruit on branches and trunk.
• Mass fruiting of Baccaurea motleyana (Phyllanthaceae).JPG — NusHub, CC BY-SA 3.0; heavy fruiting throughout the canopy.
• Young fruits of Baccaurea motleyana (Phyllanthaceae).JPG — NusHub, CC BY-SA 3.0; young fruit hanging on the tree.