Both Nusa Bailing Island and Blambangan Peninsula consist of limestone hills; they are nowadays uninhabited and forest-clad. On Nusa Bailing the forest is mixed and not conspicuously dominated by certain genera. On Blambangan the forest contains much bamboo, which points to ancient human influence, and a number of species characteristic for ‘monsoon-forest’. A few remarks on history, and data about the author’s routes, are given. Most of the plants collected are recorded in sketches of the vegetation. The f. lobata of Gmelina elliptica (Verben.) is reduced. Novelties are not reported, and it is doubtful whether the areas in question deserve much further attention for botanical exploration.