Derris ferruginea is taken as D. elegans var. vestita in Sanjappa (1992) which is now a distinct species.
Derris microptera is taken as a synonym of D. acuminata in Sanjapa (1992) but it is now a distinct species.
Sanjappa, M. 1992. Legumes of India. Bishen Singh Mahendra Pal Singh, Dehradun.