In the Journal of the Straits Branch of the Royal Asiatic Society (Jan 1900), "The Flora of Singapore" page 50, this species was listed as: flowers white; common: Garden jungle, Kranji, Chan Chu Kang.
Listed in the Singapore Red Data Book as: Critically endangered. The species only occurs in Northern Peninsular Malaysia and Southern Johore/Singapore. Most of the Southern Johore populations are gone or threatened by conversion (Symington).
Based on the current surveys there could be around 50 trees. However, all trees are over/around 395cm girth. No seedlings or smaller trees have ever been found. So the population is not regenerating and might actually go extinct when these giant trees eventually die. This Tree in the Singapore Botanic Gardens is the only one easily accessible to the public.