Thunbergia  

Vines [or shrubs], lacking cystoliths. Leaves petiolate; leaf blade margin entire to lobed to dentate. Flowers solitary or paired in leaf axils, or in terminal dichasiate thyrses, pedunculate; bracteoles leaflike, paired, enclosing calyx and most or all of corolla tube, distinct or fused along one side, persistent. Calyx much shorter than bracteoles, cupular with 10-20 subulate lobes or reduced to an entire ring. Corolla funnel-shaped, large; tube with short cylindric base then widened; limb ± equally 5-lobed. Stamens 4, often didynamous, inserted near base of corolla tube, included; anthers 2-thecous; thecae oblong or ovoid, parallel, spurred or not at base, sometimes bearded. Disk shortly annular or pulvinate. Ovary fleshy; ovules 2 per locule, collateral; style glabrous or pubescent; stigma 2-cleft, entire, or fringed. Capsule basally subglobose, apically prominently beaked, 2-4-seeded; retinacula absent. Seeds compressed to spherical, lacking trichomes.