Amongst the Dillenias, most have yellow flowers. This one has medium-sized serrated leaves and white flowers. There were no flowers for me to show but the healthy green leaves and branches used to drape all the way down to the seating height of the adjacent bench.
Fortunately, there are a few more of this species found within HortPark. A prominent one is at the Water Garden. The lucky visitors would be able to catch a glimpse of the flowers.
The attached photo showed the adventitious roots along the trunk of this tree at the forks. From the sight of it, it appears the tree branches were either damaged or not pruned off properly in the past, leaving behind the openings that gradually closed up with overlapping bark and adventitious roots.