Karyomorphology in two African species of Nesaea(N. aspera and N. cordata)of Lythraceae was studied for the first time using meristematic cells of root tips. Chromosome numbers are 2n=10 in Nesaea cordata and 2n=30 in N. aspera ; 2n=10 in N. cordata is the lowest number in the genus. The two species are similar in having the simple chromocenter type at interphase and a karyotype containing chromosomes with secondary constriction.Based on the present and earlier information, we determined the chromosome base number of Nesaea to be x=5, a number derived in Lythroideae where most genera are known to have x=8. Relationships of Nesaea with several other genera with x=5(Diplusodon, Lythrum, and Peplis)are also briefly discussed.