The new taxa Cypholophus treubii var. aciculata (Urticaceae), Polyosma rampae (Polyosmaceae) and Psychotria apiculata var. altigena (Rubiaceae) are described from montane environments in the Kaijende Highlands of Papua New Guinea. A supplementary description is provided for Solanum nolense (Solanaceae), previously known only from a fruiting collection. Synonymies are suggested for species in Cypholophus, Psychotria, and Rubus (Rosaceae).