Cytogenetic studies in the diploid and polyploid species and cytotypes of the genusThemeda, collected from India have been undertaken. Diploid species had 2n= 20 chromosomes and they wereT. anathera, T. tremula, T. strigosa, T. hookeriandT. mooneyii.The last three indicated the existance of 0 to 3 supernumerary chromosomes during meiosis. Their behaviour has been discussed. T.villosa, T. caudata, T. quadrivalvisand a cytotype ofT. triandrawere found to be tetraploids with 2n= 40 chromosomes. From the pairing behaviour it was considered that the first two were either autopolyploids with gene controlling their pairing behaviour or may be genomic allotetraploids. The other two were categorised as segmental allopolyploids. T.longispathawith 2n= 50 is a pentaploid and possibly an auto-allo-pentaploid as seen from its chromosomal behaviour and hybrid nature. The two hexaploids with 2n= 60 areT. arundinaceaandT. dacruzii.The former appeared to be a segmental allohexaploid while the latter from its cyto-morphological behaviour seems to have evolved from diploid species of T.anathera.The octaploid (2n= 80) nonaploid (2n= 90) and endecaploid (2n= 110) are cytotypes ofT. triandra.The first one has been categorised as segmental allo-octaploid while the other two have been considered as auto-alloploids. The nature of polyploidy in the species ofThemedathat were collected from different parts of India has been discussed.