Ficus villosa and Ficus sagittata are both common root climbers of primary forest in Borneo.
Root climbers start from a seedling in the the ground and grow by attaching their roots to the surface of the trunks of tall trees. Root climbing figs do not fruit until they reach sunlight in the canopy and so can be difficult to identify from the ground.
In addition the bathyphyll leaves of the juvenile plants at ground level often look quite different from the adult (acrophyll) leaves of the the canopy level branches.
Once you learn to identify the bathyphyll leaves of root climbing figs you will realise how abundant they are in wet virgin forest. In some forests such as at Temburong in Brunei or Tawau Hills in Sabah almost every old tree hosts at least one root climbing fig.
Photos and information provided by Shavez Cheema and Chun Xing WONG of 1Stop Borneo Wildlife.