P. van Royen

• De botanische expeditie 1954-1955 in Nieuw Guinea
• Eriandra, a new genus of Polygalaceae from New Guinea
• Florae Malesianae Precursores
• Provisional list of families and genera found in New Guinea and surrounding islands (Gymnospermae, Angiospermae)
• Sertulum Papuanum
• The alpine flora of New Guinea
• The genus Rubus (Rosaceae) in New Guinea
• The orchids of the high mountains of New Guinea
• The podostemaceae of the New World