Keys available in attachment at efi thread (along with difference between Solandra grandiflora and Solandra maxima)

Solandra grandiflora Sw.ShrubWestern Ghats, Evergreen Forests,  Cultivated, Native of Tropical AmericaFlora of Tamil Nadu, VOL. II, 1987Nilgiri 

Species with description & pictures in Flowers of India as on 23.5.18:

Botanical nameFamilyCommon name
Solandra grandiflora Solanaceae Cup of Gold

Floriculture in India By Gurcharan Singh Randhawa, Amitabha Mukhopadhyay (1986)- Details:
Solandra grandiflora

Flora Indica; or Descriptions of Indian plants ... Edited by W. Carey ... To ... By William Roxburgh (1874):
Solandra grandiflora