The long tubular bell-shaped flowers of cestrum nocturnum, a.k.a. Night Blooming Jasmine open at night to release their Heavenly perfume. Whilst during the day they are tightly
shut and drooping, at night they lift upwards and open wide to reveal an attractive star-shaped entrance passage.
This is to allow night pollinators, like moths or humming birds to enter and extract the
nectar from the base of the petals. Their bodies rub against the stamen and the sticky pollen at the ends of the stamen sticks to them. From there the pollen is easily transferred (by accident) to the stigma which is the female part of the flower.
As those night pollinators dance from one flower to another, they ensure the pollination of the flowers which leads to seeds, which is how plants replicate themselves.
All evening and night-scented plants require to be able to attract those night pollinators.
With poor visibility, nocturnal insects and small birds depend on their olfactory senses more so than those who are active during the day, and plants assist them by emitting a highly perfumed aroma that they can smell from miles away.
Our human sense of smell is nowhere nearly so highly tuned, but we can still enjoy the perfume of night -scented plants from a much closer proximity.
It can be argued, however, the cestrum nocturnum (Night Blooming Jasmine) has quite possibly the strongest scent flower in world, as we humans can smell it from 50 yards away, which, in human terms, is pretty amazing.