A massive Ficus deltoidea fig tree growing as a hemi-epiphyte on a Gluta velutina tree on a brackish tidal river bank near the mouth of the Lamandau River, Pangkalanbun in Central Kalimantan.
Ficus deltoidea normally grows in nutrient poor environments, for example as an epiphyte high in the canopy or as a shrub in poor kerangas soils where it can out compete other less adaptable figs. From the evidence of these photographs this individual plant first established as an epiphyte on a Gluta velutina tree and then put down roots into the (salty) mud at the base of the tree. This type of growth is typical of many hemi-epiphytic stranglers in Section Conosycea in Borneo but very rare for Ficus deltoidea.
Gluta velutina known locally as Rengas, is one of several trees in the mango family Anacardiaceae which produce sap highly toxic and irritant to humans. The sap is initially white but soon turns black. Gluta velutina occupies a specialist habitat, brackish water along river banks in mangrove forest. The large unusual fruit are also toxic and are dispersed by tidal currents not by animals. For photographs of Gluta rengas see here.
According to to Labay Dapi Ficus deltoidea grows on several different species of trees in the riverine forest and there is no specialist association with Gluta velutina.
Information and photographs thanks to Labay Dapi.
Google Maps Link: Kumai bay, Pangkalanbun, Central Kalimantan