Subsp. plebeia, which occurs in Australia and Malaysia, has the sepals laxly pubescent with distinctly more indumentum than in subsp. africana; subsp. indica Verdc. has narrower more acuminate sepals and occurs in India. The species probably also occurs in South America but more collections are necessary to elucidate the inter-relations of the infraspecific taxa of this presumably ancient species.There is a possibility that the correct name for this species should be I. biflora (L.) Pers. but the identity of Convolvulus biflorus L. is dubious.