Ten to twelve species are currently botanically recognized as belonging to the genus Solandra (D'Arcy 1991, 79*; Bartels 1993, 207*; Schultes and Farnsworth 1982, 166*). However, the taxonomy of the genus is rather confusing or, as Schultes (1979b, 150*) expressed it, "very poorly understood" https://wiki.tripsit.me/wiki/Cup_of_Gold