Family Acanthaceae
In much of the warmer world, Thunbergia alata, or black-eyed susan, is well known as a fast-growing, long-flowering, friendly creeper. In South Africa it is a general favourite as it is not fussy about soil, needs only moderate water, doesn't go rampant, is mostly evergreen and covers ugly places beautifully. It has even been honoured in the standard set of South African postage stamps. 
Black-eyed susan is probably pollinated by bees. An insect visiting the flower will touch the stigma first, with its back, and then the anthers, getting a load of pollen that is then carried to another stigma. The flowers reflect ultra violet light in a pattern that is visible to insects but not to humans. This helps insects find the centre of the flower. Seeds are perhaps ejected mechanically when the fruit splits open. A butterfly, Junonia ovithya, or the eyed pansy, and moths also visit these plants to lay eggs, for the larvae eat the leaves. Hence this creeper, being attractive to insects, helps bring birds into a garden. Birds also often nest in the thickly tangled stems.
Uses and cultural aspects
Used mainly as an ornamental plant, Thunbergia alata makes a good screen when used to cover unsightly dead trees or walls. It needs some support, as it cannot cling. Use fences, trellises, arches, arbours and pillars or a lightly shading tree. (Pergolas would probably be too big.) Alternatively, plant this creeper in groups as a ground cover, or on a bank or terraces where it can trail downwards. Hanging baskets are also a possibility.
In East Africa, black-eyed susan is used as a vegetable or stock feed. Medicinally it is used for skin problems, cellulitis, back and joint pains, eye inflammation, piles and rectal cancer. Gall sickness and some ear problems in cattle are also treated with this plant. Some people can get contact dermatitis from it.
