A new species, Diplycosia kalimantanensis P.Wilkie & Argent (Ericaceae), collected on an expedition to Gunung Besar in the Meratus mountains, South Kalimantan, is described and illustrated, and a conservation assessment provided.

Diplycosia mekonggaensis Argent & Widjaja (Ericaceae, Gaultherieae) is described and illustrated as a new species from the island of Sulawesi in Indonesia. Diagnostic characters are given and comparisons with related species are made.

New taxa and records of Diplycosia (Ericaceae) from recent expeditions to Sulawesi are described. Diplycosia balgooyi Argent, D. gallowayana Argent, D. glaucicaulis Argent, D. hendriana Argent and D. supyanii Argent are described as new species. Diplycosia minutiflora Sleumer var. glandulifera Argent is described as a new variety and the new combination D. capitata Sleumer var. crassiramea (Sleumer) Argent is made. A key to all the known species of Diplycosia from this island is provided, together with short descriptions of the previously described species.

A new species of Diplycosia (Ericaceae), Diplycosia bartolomei Ferreras & Argent, presently known only from Mt. Mingan in the border region between Aurora and Nueva Ecija provinces in Luzon, Philippines, is described. Comments on possible relationships and differences from other Philippine species are given.