Any of a series of structures composed of septins and septin-associated proteins localized to the cleavage plane which are involved in cytokinesis. [ http://www.ncbi.nlm.nih.gov/pubmed/16009555 http://www.ncbi.nlm.nih.gov/pubmed/15774761 http://www.ncbi.nlm.nih.gov/pubmed/12101122 ]