Revision of the Synechococcales (Cyanobacteria) through recognition of four families including Oculatellaceae fam. nov. and Trichocoleaceae fam. nov. and six new genera containing 14 species Author Mai, Truc Department of Biology, John Carroll University, 1 John Carroll Blvd., University Heights, Ohio 44118, USA & Department of Plant and Environmental Sciences, New Mexico State University, Skeen Hall Room N 127, P. O Box 30003 MSC 3 Q, Las Cruces, New Mexico 88003, USA. Author Johansen, Jeffrey R. Department of Biology, John Carroll University, 1 John Carroll Blvd., University Heights, Ohio 44118, USA & Department of Botany, Faculty of Science, University of South Bohemia, 31 Branišovská, 37005 České Budějovice, Czech Republic Author Pietrasiak, Nicole Department of Plant and Environmental Sciences, New Mexico State University, Skeen Hall Room N 127, P. O Box 30003 MSC 3 Q, Las Cruces, New Mexico 88003, USA. Author Bohunická, Markéta Author Martin, Michael P. Department of Biology, John Carroll University, 1 John Carroll Blvd., University Heights, Ohio 44118, USA text Phytotaxa 2018 2018-08-16 365 1 1 59 http://dx.doi.org/10.11646/phytotaxa.365.1.1 journal article 10.11646/phytotaxa.365.1.1 1179-3163 Tildeniella Mai, Johansen et Pietrasiak gen. nov. Description:— Filaments with or without sheath, straight, flexuous or spirally coiled. Sheath thin, firm, colorless when present. Trichomes untapered, not constricted to slightly constricted at the crosswalls, with thin translucent crosswalls that are sometimes hardly visible, under 3 μm wide, without necrdia and hormogonia. Cells longer than wide. End cells rounded. Phylogenetically distinct from all other genera in the Oculatellaceae . Etymology:— named for Josephine Tilden, a prominent American cyanobacteriologist of the mid-20th century. Type species:— Tildeniella torsiva Mai, Johansen et Pietrasiak sp. nov.