The chromosome numbers of 11 species, belonging to different families, are listed in this paper. The materials, kindly supplied by Dr. K. U. Kramer and W. H. A. Hekking, and by Dr. W. A. E. van Donselaar-ten Bokkel Huinink, were collected during their stay in Surinam, in 1960/1961 and 1958/1959 respectively. The chromosome counts are based on the study of roottip-mitoses. The roots were fixed in Karpechenko, embedded in paraffin and sectioned at 15 ft, and stained according to Heidenhain’s haematoxylin method. The species are listed in the table.