1992 Volume 57 Issue 2 Pages 173-179
Karyology of thirteen taxa belonging to four genera, Pinnularia, Gyrosigma, Navicula and Gomphonema, was studied. Chromosome numbers determined for different taxa ranged from 2n=6 to 2n=64. Chromosomes were mostly dot-like or rod-like and varied from 0.25 to 1.7μm in size. Metaphase organisation of chromosomes was found to be either plate or ring. Chromosome numbers recorded in the present study are new to science.