Thanks to the kind intermediary of the Director of the Botanic Gardens at Kew, I had the opportunity to work out the Cyperaceae of the expedition mentioned above. The 25 numbers collected belong to 19 species. From the 8 species belonging to the Mapanieae, 5 are new to science. Two species of Carex are endemic for Borneo. All the other species are either cosmopolitic or at least more widely spread outside this island.