sentences:  From 1969 to the late 1990s botanist Don B. Foreman, who was based in Papua New Guinea and Australia, collected numerous additional species, which he formally described before he wrote the comprehensive reviews and flora treatments for the two regions; notably in the authoritative "Handbooks of the Flora of Papua New Guinea" (1978–1995, to date 3 volumes), he wrote the chapters for Proteaceae and other families; and in the authoritative "Flora of Australia" (1981–, 60 volume series) he wrote the treatment of "Helicia".From the 1990s botanist Richard C. K. Chung, based in Malaysia, published new species formal descriptions and a revision of the 13 species occurring in Borneo.In total, approximately 100 species have been formally scientifically described.