Karyological analysis including determination of somatic chromosome number, total chromosome length, volume and karyotype formula and in situ estimation of 4C-nuclear DNA amount were carried out on 14 different species and varieties of the genera Calathea, Maranta and Stromanthe. The 4C nuclear DNA amount was estimated through Feulgen microspectrophotometry following single wavelength method and expressed in arbitrary units of relative absorbances. The variation in 4C DNA amounts between the species of Calathea was not distinct but in two species of Maranta, a notable variation in nuclear DNA amount was recorded. In addition, the amount of nuclear DNA did not show direct correlation with the total chromosome length and volume. The absence of wide difference in nuclear DNA content at an interspecific level might have some adaptive value. © 1984 Indian Academy of Sciences.