Why it's called 'Clock ' vine, I do not know. It doesn't resemble a clock, a watch or any other mechanical means of telling time. But I believe this species has the most dramatic floral presentation in the genus 'Thunbergia'.
The flowers are dangling under the roof of a gazebo. I hope to achieve this effect with our Clock vine someday.
From then on it became a 'must have' for our garden. On one of her routine trips from the city to the farm, mother spotted a house with Clock vines on their pergola. She politely asked for cuttings and she was able to get a few stems.
Months after that we have our own Thunbergia mysorensis in our garden. It may not be as thick and robust as the one I saw but someday it will be. It's been trained to climb over a makeshift trellis and it's been growing well so much so that it started to bloom.