Close-up view:

According to the Flora Singapura website (that no longer exist), there are 2 forms of this tree in Singapore, namely Pometia pinnata f. alnifolia and Pometia pinnata f. glabra. Based on inflorescence and leaf characteristics, the tree has at least 8 forms [1].

In October 2012, I obtained the fruits below from a local fruit stall. The fruits stall were labelled in Chinese as "Brazil Longan". Its shell was much thicker and harder than Longan (Dimocarpus longan subsp. longan). The flesh is slightly yellowish, firmer and less sweet compared to Longan. At the end of the search via the Internet, I ended up with its identity as the fruit of this tree. It is likely to be from another form of Pometia pinnata as the fruit from Pometia pinnata f. glabra (above) is more elongated.

Reference:

Jacobs, M. 1962. Pometia (Sapindaceae), a study in variability. Reinwardtia 6: 109-144.