Thunbergia is the genus of the flowering plant in the family Acanthaceae, a native of tropical regions of Africa. It was named after a Swedish physician, Carl Thunberg (1743-1828) who had been a pupil of Linnaeus, according to the book, The Plant Lover's Companion by Julia Brittain. Thunberg "traveled for several years as a ship's surgeon and visited many distant and exotic destinations including South Africa, where he traveled into remote areas collecting plants".
There are several species of thunbergias which are considered to be "Vigorous annual or perennial vines and shrubs growing to 2 -8 meter tall," according to Wikipedia.
I have seen many beautiful light blue flowers of thunbergia grandiflora growing wildly on fences on my recent trip to Southern California.
I once had a thunbergia with dark blue flower but have not seen the plants around here again until this year.
The three I have now are thunbergia alata or Black-Eyed Susan vine. Two were planted along the sides of my front steps, climbing up on the railings. Both have been producing a few flowers which started out as light yellow, turning to darker yellow and later to reddish orange. This cultivar is called Spanish Eye.
I purchased another thunbergia as a well-established plant called African Sunset about two or three weeks ago. It came in a container with a trellis. I decided to keep it in the same container and let it climb up on the small evergreen tree.
I have been enjoying new blooms of brick color with dark center everyday and there are countless new buds on the plant. The information on HowStuffWorks indicates that "Plants in containers will also bloom over winter in sunny windows".