Depending on the author, the name Oldenlandia salzmannii is given either as a synonym of Hedyotis salzmannii (e.g. Kasselmann (2010))1 or as an accepted name (e.g. www.theplantlist.org).
More recent research results (Groeninckx & others (2009))2 show that the species is more closely related to, for example, Bouvardia, Manettia and Spermacoce species than to Oldenlandia and Hedyotis species in the narrower sense. So far, however, it has probably not yet been decided which genus name the species hitherto called H. salzmannii or O. salzmannii will finally receive.
References and further reading: