Hoya of Sulawesi, Indonesia: A checklist, two new species, a new subspecies and six new records

Two new Hoya R.Br. species and a new subspecies, Hoya towutiensis S.Rahayu, R.P.P.Ahmad & Rodda, Hoya mamasa S.Rahayu, R.P.P.Ahmad & Rodda and Hoya mamasa subsp.longicorolla S.Rahayu, R.P.P.Ahmad & Rodda, are described from Sulawesi, Indonesia. A checklist of Hoya of Sulawesi is published, including 30 species and one subspecies, six of which are newly recorded. Hoya tsiangiana P.T.Li is typified and considered a new synonym of Hoya australis R.Br. ex J.Traill s.l.