In Malesia there are 37 genera, of which 29 are native. The largest native genus is Trichosanthes with 43 species, followed by Pilogyne (with 14 species), Neoachmandra (with 12 species), Momordica, Neoalsomitra, Urceodiscus (with 6 species each), Gymnopetalum, Gynostemma, Kedrostis, Mukia (with 3 species each), Indomelothria, Scopellaria, Thladiantha (with 2 species each), and Alsomitra, Anangia, Baijiania, Bayabusua, Benincasa, Borneosicyos, Coccinia, Diplocyclos, Gomphogyne, Hodgsonia, Luffa, Muellerargia, Papuasicyos, Siraitia, Solena, Zanonia (with 1 species each). Altogether there are 121 native species in Malesia, comprising 152 taxa when one includes infraspecific taxa. Cultivated and frequently running wild are Citrullus, Cyclanthera, Lagenaria, Luffa, Sechium, Trichosanthes (with 1 species each), Cucurbita (with 3 species), and Cucumis (with 2 species). Introduced and running wild are Cayaponia and Melothria (with 1 species each). The introductory part consists of 18 pages and includes paragraphs on distribution, ecology, taxonomy, pollination, dispersal, sexual condition, morphology, uses, wood anatomy (by P. Baas), and pollen morphology (by C.B. Mennes & R.W.J.M. van der Ham). General and regional keys to the species are given. For each species references, synonymy, typification, a description with distribution, habitat, and often also field-notes and notes on characters, relationships, etc. are presented. The treatment is illustrated with 98 line drawings, of which 97 by J.H. van Os (Leiden) and with 33 plates (32 colour plates).