The 5 o'clock tree

Have you heard of this tree before? I am sure you know this tree as it is commonly known as the Rain Tree. It is a common roadside tree in Singapore. Ever since I read the book, Durians are not only fruits, Little One and I had been observing Rain Trees. We noticed the leaflets would close during rainy days and evening. We even start to observe whether the leaflets would close at 5 o'clock.
These are the results.

12 noon

5 o'clock

Ehhhh...... sometimes, the leaflets close but sometimes, they do not. So what is wrong?

5 o'clock

After searching the internet, this is the explanation:

The tree’s leaflets close just before sunset. This is why it is called the Pukul Lima in Malay, which means ‘five o’clock’. The sunset hour in Singapore and Malaysia used to be 5 pm before changes were made to Standard Time in the early 1980s.

-Nparks

If you love to know more about this tree, read the below sources.

Sources:
https://www.nparks.gov.sg/activities/family-time-with-nature/recommended-activities/know-10-trees/1-rain-tree

https://www.nparks.gov.sg/gardens-parks-and-nature/heritage-trees/ht-2014-228

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