Among the collections made by H. E. ROMBOUTS from 1935— 1938 on the expeditions to the Suriname-Brazil frontier there are a number of Euphorbiaceae which are either new, or rare. As I was engaged in other work I could not begin the study of these specimens before August of this year. Because of the international troubles I have not been able to secure type-specimens from foreign herbaria, so that in some cases my interpretation of earlier described species may be wrong, though most of the problems could be solved satisfactory with the aid of the material preserved at Leiden and Utrecht. Most of these specimens were collected by ROMBOUTS on the Great Savanna near the sources of the Sipaliwini River, which forms part of the boundary between Brazil and Suriname. Former studies on ROMBOUTS’ collections had shown already that this region is comparatively rich in rare or new species. It would be of the utmost importance if a botanist could visit this region to collect on a large scale and to make a study of the vegetation. Without doubt the results would justify the comparatively low expenses needed for such an expedition.