Galactomannan was localized by scanning and transmission electron microscopy on the cells and cell walls of Schizosaccharomyces pombe. The markers were prepared from colloidal gold granules labelled with an alpha-galactopyranosyl-binding lectin isolated from the seeds of Bandeiraea simplicifolia. Part or all of this alpha-galactomannan was present in the outer layer of the cell wall and was uniformly distributed even on the fission scars.