Macaranga polyadenia is a small tree up to tall in the family Euphorbiaceae, found in New Guinea, the Bismarck Archipelago, the Solomon Islands, Vanuatu and the Australian state of Queensland. It usually inhabits lowland palm forest and seasonally flooded swamp forest, but may occur up to above sea level. It was first described in 1919 by botanists Ferdinand Albin Pax and Käthe Hoffmann.
, this species has been assessed to be of least concern by the International Union for Conservation of Nature (IUCN) and by the Queensland Government under its Nature Conservation Act.