Fittingia headsiana is described from previously unknown environments in Papua New Guinea's southern ranges. The new species is uniquely distinguished by its purple fruits disposed in large panicles, and is one of only two congeners capable of achieving arborescent statures. With the addition made here, Fittingia is now represented by nine species restricted to the New Guinea mainland, of which only five were known at the time of the last generic revision. A synoptical key to the modern species is included as an amendment to the existing treatment.