Key to species of Heterostemma sect. Oianthus in India

1. Corolla discoid or depressed globose or vertically compressed globose ......................... 2

1. Corolla urceolate or tubular ............................ 4

2. Corona lobes with inner appendages ................ ...................................................... H. vasudevanii

2. Corona lobes without inner appendages........ 3

3. Leaves ovate or broadly or narrowly ovate-lanceolate or ovate-cordate; corolla hairy inside................................................ H. beddomei

3. Leaves elliptic-oblong to ovate-oblong; corolla glabrous ........................................ H. disciflorum

4. Corolla tubular or rarely ovoid-urceolate; corona lobes rounded at apex........ H. deccanense

4. Corolla perfectly urceolate; corona lobes 3-toothed at apex......................... H. urceolatum