At close quarters the Thunbergia alata floral black eye isn’t as round as one might think. The one in picture is more pentagonal, although not quite regular in shape. The flower is about 3 cm wide.
The five petal lobes also differ in size and shape. Some are broad-tipped and variably notched, others rounded or uneven. The lobe surfaces are not really smooth; straight-veined from the base.
The jet-black eye may also surprise. Some plants with clear orange flowers are sometimes seen.
Bees feature among the plant's pollinators.
There are several garden cultivars of this plant in existence (Manning, 2009; Pooley, 1998; Onderstall, 1996; iNaturalist).