Abacella pertusa Maslov † (basis of record)
Abacum rudis (A. Combaz) P. Pittau † (basis of record)
Abas wittii (Grunow) R. Ross & P.A. Sims, 1980 (basis of record)
Abbotia araneosa L.P. Perestenko, 1975 accepted as Neoabbottiella araneosa (L.P. Perestenko) S.C. Lindstrom, 1985 (basis of record)
Abbottella concinna Hollenberg, 1967 (basis of record)
Abbottia araneosa L.P. Perestenko, 1997 accepted as  (basis of record)
Abedinium dasypus (Cachon & Cachon-Enjumet) A.R. Loeblich Jr. & A.R. Loeblich III, 1966 (basis of record)
Abratopdinium cardioforme S. Mao & B.A.R. Mohr, 1992 † (basis of record)
Abratopdinium kerguelense S. Mao & B.A.R. Mohr, 1992 † (basis of record)
Abrotanifolia barbata Stackhouse, 1809 accepted as Cystoseira barbata (Stackhouse) C. Agardh, 1820 (basis of record)
Abrotanifolia discors (Linnaeus) Stackhouse (basis of record)
Abrotanifolia foeniculacea (Linnaeus) Stackhouse (basis of record)
Abrotanifolia loeflingii Stackhouse (basis of record)
Abrotanifolia mucronata (Turner) Stackhouse (basis of record)
Abroteia orbicularis J.G. Agardh, 1876 (basis of record)
Abroteia suborbicularis (Harvey) J.G. Agardh, 1878 (basis of record)
Abruptophycus colonialis Vologdin † (basis of record)
Abruptophycus compositus Vologdin † (basis of record)
Acaciella angepena Preiss † (basis of record)
Acaciella augusta Preiss † (basis of record)
Acanthaulax acanthosphaera (Sarjeant) Sarjeant † (basis of record)
Acanthaulax aceras (Eisenack) Stover & Evitt † (basis of record)
Acanthaulax aculeata (Klement) Stover & Evitt † (basis of record)
Acanthaulax angulosa (Gitmez) Stover & Evitt † (basis of record)
Acanthaulax paliuros (Sarjeant) Sarjeant † (basis of record)
Acanthaulax spinosissima (Deflandre) Sarjeant † (basis of record)
Acanthaulax venusta (Klement, 1960) Sarjeant † (basis of record)
Acanthina bullosa Korde † (basis of record)
Acanthina multiformis Korde † (basis of record)
Acanthobolus brasiliensis Kützing, 1843 accepted as Endocladia vernicata J.G. Agardh, 1841 (basis of record)
Acanthoceras azoricum (Meneghini) Kützing accepted as Ceramium azoricum Meneghini accepted as Ceramium echionotum J.G. Agardh, 1844 (basis of record)
Acanthoceras dalmaticum (Meneghini) Frauenfeld accepted as Ceramium dalmaticum Meneghini (basis of record)
Acanthoceras echinophorum (Meneghini) Frauenfeld (basis of record)
Acanthoceras echionotum (J.G. Agardh) Kützing (basis of record)
Acanthoceras madeburgensis Hongimann, 1910 (basis of record)
Acanthoceras magdeburgense Honigmann accepted as Acanthoceras zachariasii (Brun) Simonsen (basis of record)
Acanthoceras oxyacanthum Kützing (basis of record)
Acanthoceras shuttleworthianum Kützing, 1842 accepted as Ceramium shuttleworthianum (Kützing) Rabenhorst, 1847 (basis of record)
Acanthoceras transcurrens Kützing accepted as Ceramium echionotum J.G. Agardh, 1844 (basis of record)
Acanthoceras zachariasii (Brun) Simonsen (basis of record)
Acanthocerataceae Round, Crawford & Mann, 1990 accepted as Chaetocerotaceae Ralfs, 1861 (basis of record)
Acanthochloris bacillifera Pascher (basis of record)
Acanthochloris brevispinosa Pascher, 1930 (basis of record)
Acanthochloris hungarica Palik (basis of record)
Acanthochloris ingens Margalef, 1956 (basis of record)
Acanthochloris scherffelii Pascher (basis of record)
Acanthochloris verrucosa Ettl (basis of record)
Acanthochondria falkenbergii Weber-van Bosse, 1888 accepted as Acanthophora dendroides Harvey, 1855 (basis of record)
Acanthochrysis echinococcus Conrad, 1931 (basis of record)
Acanthochrysis echinocystus (Conrad) Conrad (basis of record)
Acanthochrysis fusiformis Conrad (basis of record)
Acanthocladia Ardissone, 1886 (basis of record)
Acanthocladia anglica Bennett (basis of record)
Acanthocladia asperrima Ruprecht (basis of record)
Acanthocladia hamulosa Ruprecht (basis of record)
Acanthocladia muricata (Postels & Ruprecht) Ruprecht (basis of record)
Acanthococcus acicularis (J.G. Agardh) J.G. Agardh, 1852 accepted as Mychodea aciculare (J.G. Agardh) Kraft, 1978 (basis of record)
Acanthococcus aciculiferus Lagerheim, 1883 accepted as Trochiscia aciculifera (Lagerheim) Hansgirg, 1888 (basis of record)
Acanthococcus adelphinus Montagne (basis of record)
Acanthococcus anglicus Bennett (basis of record)
Acanthococcus antarcticus J.D. Hooker & Harvey, 1845 (basis of record)
Acanthococcus argutus Reinsch (basis of record)
Acanthococcus asper Reinsch accepted as Trochiscia aspera (Reinsch) Hansgirg, 1888 (basis of record)
Acanthococcus bernardinensis Chodat (basis of record)
Acanthococcus ewingii Harvey, 1860 accepted as Mychodea hamata Harvey, 1860 (basis of record)
Acanthococcus gracilaria Sonder, 1853 accepted as Mychodea gracilaria (Sonder) Sonder, 1880 (basis of record)
Acanthococcus granulatus Reinsch, 1886 accepted as Trochiscia granulata (Reinsch) Hansgirg, 1888 (basis of record)
Acanthococcus hirtus (Reinsch) Reinsch (basis of record)
Acanthococcus hirtus (Reinsch) Lagerheim, 1883 accepted as Trochiscia hirta (Reinsch) Hansgirg, 1888 (basis of record)
Acanthococcus hystrix Reinsch, 1886 accepted as Trochiscia hystrix (Reinsch) Hansgirg, 1888 (basis of record)
Acanthococcus insignis Reinsch (basis of record)
Acanthococcus obtusangulus Harvey, 1863 accepted as Mychodea hamata Harvey, 1860 (basis of record)
Acanthococcus obtusus Reinsch (basis of record)
Acanthococcus pachydermus Reinsch (basis of record)
Acanthococcus plicatus Reinsch (basis of record)
Acanthococcus pusillus (Harvey) Harvey, 1863 accepted as Mychodea pusilla (Harvey) J.G. Agardh, 1872 (basis of record)
Acanthococcus reinschii (Hansgirg) Printz (basis of record)
Acanthococcus reticularis Reinsch accepted as Trochiscia reticularis (Reinsch) Hansgirg, 1888 (basis of record)
Acanthococcus retusus Reinsch (basis of record)
Acanthococcus spinosus Reinsch (basis of record)
Acanthococcus spinuliger (J.G. Agardh) J.G. Agardh, 1851 accepted as Acanthococcus antarcticus J.D. Hooker & Harvey, 1845 (basis of record)
Acanthococcus spinuligerus (J.G. Agardh) J.G. Agardh (basis of record)
Acanthococcus sporoides Reinsch (basis of record)
Acanthococcus subulatus (C. Agardh) J.G. Agardh, 1852 accepted as Agardhiella subulata (C. Agardh) Kraft & M.J. Wynne, 1979 (basis of record)
Acanthocodium fragile Suringar, 1867 accepted as Codium fragile (Suringar) Hariot, 1889 (basis of record)
Acanthodiacrodium abortivum Timofeev, 1959 † (basis of record)
Acanthodiacrodium adelphicum Timofeev, 1959 † (basis of record)
Acanthodiacrodium anceps Timofeev, 1959 † (basis of record)
Acanthodiacrodium angustizonale G. Burmann, 1968 † (basis of record)
Acanthodiacrodium angustum (Downie, 1958) Combaz, 1967 † (basis of record)
Acanthodiacrodium arburense P. Pittau † (basis of record)
Acanthodiacrodium barbullatum Timofeev, 1959 † (basis of record)
Acanthodiacrodium capsulare Timofeev, 1959 † (basis of record)
Acanthodiacrodium commune Timofeev, 1959 † (basis of record)
Acanthodiacrodium concaviusculum G. Burmann, 1970 † (basis of record)
Acanthodiacrodium conforme Timofeev, 1959 † (basis of record)
Acanthodiacrodium constrictum (Deunff) Deflandre & Deflandre-Rigaud † (basis of record)
Acanthodiacrodium convexum Timofeev, 1959 † (basis of record)
Acanthodiacrodium cornutum Timofeev, 1959 † (basis of record)
Acanthodiacrodium costatum G. Burmann, 1968 † (basis of record)

 Taxonomic remark

 for Dermocarpales

Type genus Dermocarpa not listed in Komárek et al., 2014 and listed as problematic/unaccepted in CyanoDB (type ... [details]