Thunbergia gregorii  Thunbergia gregorii, commonly known as orange clockvine or orange trumpet vine, is a herbaceous perennial climbing plant species in the family Acanthaceae, native to East Africa and sometimes cultivated as an ornamental vine. The bright, pure all-orange flowers distinguish it from the related black-eyed Susan vine ("Thunbergia alata"). Spencer Le Marchant Moore described the species in 1894, naming it after John Walter Gregory. Within the genus "Thunbergia", it is most closely related to "T. alata", the two being placed in the subgenus "Parahexacentris". The common name of clockvine relates to the vine spiralling upwards in a clockwise direction. "Thunbergia gregorii" is an evergreen vine that grows to 8–10 ft. tall, or if left without support can become an extensive groundcover. It looks like the related black-eyed Susan vine ("T. alata"), but without the black eye. "Thunbergia gregorii" is native to east Africa, and is pollinated by bees. Hardy to -1 C, "Thunbergia gregorii" flowers more profusely and even year-round in warmer climates, while restricted to summer and autumn in cooler climates. Propagation is by cuttings taken in the summer.