Koompassia excelsa(Local name Mangaris) growing near the entrance gate to Tabin Wildlife Reserve in Sabah. K. excelsa is the largest bean plant (Family Leguminosae/ Fabaceae) in the world, with one giant individual recorded growing to 88 m.
A second species of Koompassia, K. malaccensis (Local name Kempas or Impas) is also common in lowland forest throughout Borneo. K. malaccensis has been recorded up to 60 m tall.
In most of Borneo’s dipterocarp forest the canopy tops out at 40-50 m so both Koompasia species are emergents , i.e. they tower above a canopy of smaller dipterocarp trees. Due to their height and prominent smooth white trunks Mangaris and Kempas are easy to recognise.
Koompassia flower morphology indicates that the pendant strings of tiny white flowers are targeted for pollination by nectar bats although bees are involved as well. The papery seeds (beans with a single wing) are wind dispersed.
The reasons for the pale trunk and the emergent height are obvious. Both nectar bats and giant honey bees Apis dorsata fly long distances at night searching for nectar sources. By providing abundant food on a prominent white trunk above the canopy Koompasias will be easy to find by nocturnal nomadic pollinators.