Heterochromatin in Encephalartos [Cycadaceae]

Fluorescence analysis of the karyotypes of two species of Encephalartos has revealed the presence of considerable amounts of heterochromatin. The heterochromatin is present mainly on two of the chromosome pairs, in one of which it is associated with the nucleolar organising regions. The significance of the heterochromatin is discussed relative to the highly specialised nature of cycad species.