Do you know that besides the azalea and other more widely recognized plants and flowers, NTU campus is home to the native Barringtonia racemosa flower tree, also known as the powder-puff tree? During the summer, the nocturnal blossoms of our powder-puff trees can be spotted all around campus, painting picturesque visions of fireworks lighting up the summer nights.

Barringtonia racemosa flowers are usually white or pink and bloom in pendulous sprays during their flowering season. Blooming simultaneously, these powder-puff trees fill the eye with explosions of pink, white and green while exuding an aromatic and intoxicating fragrance.

But what is it that gives these nighttime flowers their fascinating aroma?
Equipped with scientific training and profound curiosity, a group of experts from NTU's School of Forestry and Resource Conservation set out to find the answer.

According to Distinguished Professor Shang-Tzen Chang and graduate student Qun-Ya Lin, the flowers begin to bloom around three to four o'clock in the afternoon, and usually reach full bloom between seven and eight in the evening. The blossoms then gradually begin to wilt after six o'clock the following morning.

The team concluded that the best time to view the Barringtonia racemosa flowers is during the first hour or so after midnight.

To explain the flower's mysterious aroma, the group designed an in situ sampling device to capture and monitor the flower's fragrance hourly. Analysis of the samples showed that the aromatic emissions, whose main composition includes linalool, phenylacetaldehyde, germacrene D and (E,E)-α-farnesene, peak between 23:00 and 02:00. Further analysis revealed that linalool and phenylacetaldehyde are the main sources of the flower's aroma, and are exuded as a means of survival and reproduction. The team also found that, besides smelling pleasant, the sweet, rich and unique Barringtonia racemosa fragrance is calming and helps relieve tension.

If on a late night this summer you happen upon a powder-puff tree in full bloom, we hope you will take the time to enjoy its bursting blossoms and aromatic scent during its brief moment of glory.