thunbergia retz. is a genus of flowering plants in the family acanthaceae, native to tropical regions of africa, madagascar and southern asia. its members are known by various names, including thunbergias; clockvine on its own usually refers to "thunbergia grandiflora", while "thunbergia alata" is often known as black-eyed susan vine or just black-eyed susan (not to be confused with other flowers called black-eyed susan). orange clockvine is the name of "thunbergia gregorii".