In the species-rich tropics, rapid assessment surveys have become a widely employed method for acquiring bioestimates of site value. Some of Papua New Guinea's most pristine habitats are currently being explored with such surveys. Five new species collected during these investigations are described here. The novelties are Psychotria kamialii sp. nov. (Rubiaceae), P. muellerdomboisii sp. nov., P. pseudomaschalodesme sp. nov., P. wiakabui sp. nov., and Solanum symonianum sp. nov. (Solanaceae). Taxonomic notes are also provided for Aglaia puberulanthera (Meliaceae), and Palmeria gracilis (Monimiaceae).