A special issue of Acta Botanic Croatica (vol. 68; no 2), which includes 22 papers presented at the 20th International Diatom Symposium has been published. Contents and papers in pdf. files may be found on http://hrcak.srce.hr/acta-botanica-croatica. For information and orders of the edition please contact: Acta Botanica Croaticae-mail: acta@biol.pmf.hrweb: www.abc.botanic.hr