• Acanthobolus brasiliensis Kützing, 1843 accepted as Endocladia vernicata J.G. Agardh, 1841
• Acanthococcus acicularis (J.G. Agardh) J.G. Agardh, 1852 accepted as Mychodea aciculare (J.G. Agardh) Kraft, 1978
• Acanthococcus aciculiferus Lagerheim, 1883 accepted as Trochiscia aciculifera (Lagerheim) Hansgirg, 1888
• Acanthococcus adelphinus Montagne
• Acanthococcus anglicus Bennett
• Acanthococcus antarcticus J.D. Hooker & Harvey, 1845
• Acanthococcus argutus Reinsch
• Acanthococcus asper Reinsch accepted as Trochiscia aspera (Reinsch) Hansgirg, 1888
• Acanthococcus bernardinensis Chodat
• Acanthococcus ewingii Harvey, 1860 accepted as Mychodea hamata Harvey, 1860
• Acanthococcus gracilaria Sonder, 1853 accepted as Mychodea gracilaria (Sonder) Sonder, 1880
• Acanthococcus granulatus Reinsch, 1886 accepted as Trochiscia granulata (Reinsch) Hansgirg, 1888
• Acanthococcus hirtus (Reinsch) Lagerheim, 1883 accepted as Trochiscia hirta (Reinsch) Hansgirg, 1888
• Acanthococcus hirtus (Reinsch) Reinsch
• Acanthococcus hystrix Reinsch, 1886 accepted as Trochiscia hystrix (Reinsch) Hansgirg, 1888
• Acanthococcus insignis Reinsch
• Acanthococcus obtusangulus Harvey, 1863 accepted as Mychodea hamata Harvey, 1860
• Acanthococcus obtusus Reinsch
• Acanthococcus pachydermus Reinsch
• Acanthococcus plicatus Reinsch
• Acanthococcus pusillus (Harvey) Harvey, 1863 accepted as Mychodea pusilla (Harvey) J.G. Agardh, 1872
• Acanthococcus reinschii (Hansgirg) Printz
• Acanthococcus reticularis Reinsch accepted as Trochiscia reticularis (Reinsch) Hansgirg, 1888
• Acanthococcus retusus Reinsch
• Acanthococcus spinosus Reinsch
• Acanthococcus spinuliger (J.G. Agardh) J.G. Agardh, 1851 accepted as Acanthococcus antarcticus J.D. Hooker & Harvey, 1845
• Acanthococcus spinuligerus (J.G. Agardh) J.G. Agardh
• Acanthococcus sporoides Reinsch
• Acanthococcus subulatus (C. Agardh) J.G. Agardh, 1852 accepted as Agardhiella subulata (C. Agardh) Kraft & M.J. Wynne, 1979
• Acanthotylus heredia (Clemente) Kützing, 1843 accepted as Phyllophora heredia (Clemente) J.G. Agardh, 1842
• Acrotylus australis J.G. Agardh, 1849
• Acrotylus clavatus Harvey, 1853 accepted as Corynomorpha clavata (Harvey) J.G. Agardh, 1872
• Acrotylus prismaticus (J.G. Agardh) J.G. Agardh, 1851 accepted as Corynomorpha prismatica (J.G. Agardh) J.G. Agardh, 1876
• Actinococcus aggregatus F. Schmitz, 1893 accepted as Gymnogongrus griffithsiae (Turner) C.F.P. Martius, 1833
• Actinococcus botrytis L. Gain
• Actinococcus chiton M.A. Howe, 1914
• Actinococcus exul R.K.F. Pilger
• Actinococcus gelidii V.F. Schiffner
• Actinococcus hennedyi Harvey, 1857 accepted as Haemescharia hennedyi (Harvey) K.L. Vinogradova & T. Yacovleva, 1989
• Actinococcus latior F. Schmitz, 1893 accepted as Gymnogongrus dilatatus (Turner) J.G. Agardh, 1851
• Actinococcus mollis M.A. Howe, 1914
• Actinococcus peltaeformis F. Schmitz, 1893 accepted as Gymnogongrus crenulatus (Turner) J.G. Agardh, 1851
• Actinococcus roseus Suhr ex Kützing, 1843 accepted as Coccotylus truncatus (Pallas) M.J. Wynne & J.N. Heine, 1992
• Actinococcus simplicifilum J.G. Agardh
• Actinococcus subcutaneus (Lyngbye ex Hornemann) Rosenvinge, 1893 accepted as Coccotylus truncatus (Pallas) M.J. Wynne & J.N. Heine, 1992
• Agardhiella baileyi (Harvey ex Kützing) W.R. Taylor, 1970 accepted as Agardhiella subulata (C. Agardh) Kraft & M.J. Wynne, 1979
• Agardhiella coulteri (Harvey) Setchell, 1897
• Agardhiella floridana (Kylin) P.W. Gabrielsen ex Guimarães & Oliviera, 1996
• Agardhiella gaudichaudii (Montagne) P.C. Silva & Papenfuss, 1979 accepted as Sarcodiotheca gaudichaudii (Montagne) P.W. Gabrielson, 1982
• Agardhiella mexicana E.Y. Dawson, 1944
• Agardhiella ramosissima (Harvey) Kylin, 1932
• Agardhiella robusta (Greville) Børgesen, 1932 accepted as Solieria robusta (Greville) Kylin, 1932
• Agardhiella subulata (C. Agardh) Kraft & M.J. Wynne, 1979
• Agardhiella tenera (J.G. Agardh) F. Schmitz, 1897 accepted as Agardhiella subulata (C. Agardh) Kraft & M.J. Wynne, 1979
• Agardhiellopsis cretacea Lemoine †
• Ahnfeltiopsis catenata (Yendo) Masuda, 1993
• Ahnfeltiopsis chnoosporoides (T. Tanaka & Pham-Hoàng Hô) Masuda, 1993
• Ahnfeltiopsis complicata (Kützing) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis concinna (J.G. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis densa (J.G. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis devoniensis (Greville) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis divaricata (Holmes) Masuda, 1993
• Ahnfeltiopsis durvillei (Bory de Saint-Vincent) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis fastigiata J.A. Lewis & Womersley, 1994
• Ahnfeltiopsis flabelliformis (Harvey) Masuda, 1993
• Ahnfeltiopsis furcellata (C. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis gigartinoides (J.G. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis glomerata (J.G. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis gracilis (Yamada) Masuda, 1993
• Ahnfeltiopsis guangdongensis B.-M. Xia & Y.-Q. Zhang, 2000
• Ahnfeltiopsis hainanensis B.-M. Xia & Y.-Q. Zhang, 2000
• Ahnfeltiopsis humilis (Lindaeur) J.A. Lewis & Womersley, 1994
• Ahnfeltiopsis intermedia (Kylin) Stegenga, Bolton & R.J. Anderson, 1997
• Ahnfeltiopsis leptophylla (J.G. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis linearis (C. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis masudae B.-M. Xia & Y.-Q. Zhang, 2000
• Ahnfeltiopsis okamurae P.C. Silva & DeCew, 1992
• Ahnfeltiopsis pacifica P.C. SIlva & DeCew, 1979
• Ahnfeltiopsis paradoxa (Suringar) Masuda, 1993
• Ahnfeltiopsis polyclada (Kützing) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis pusilla (Montagne) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis pygmaea (J.G. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis quinhonensis (Pham-Hoang Ho) Masuda, 1993
• Ahnfeltiopsis serenei (E.Y. Dawson) Masuda, 1993
• Ahnfeltiopsis smithii (W.R. Taylor) K.M. Dreckmann & I. Stout, 1993
• Ahnfeltiopsis triquetrifolia Masuda & Kogame, 1998
• Ahnfeltiopsis vermicularis (C. Agardh) P.C. Silva & DeCew, 1992
• Ahnfeltiopsis yamadae (Segawa) Masuda, 1993
• Amphibrachia hymenocladioides J.G. Agardh
• Amphiplexia hymenocladioides J.G. Agardh, 1892
• Amphiplexia racemosa (J.G. Agardh) Kraft, 1977
• Amphiplexia splachnoides (Harvey) Kraft, 1977 accepted as Webervanbossea splachnoides (Harvey) De Toni fil., 1936
• Amylophora coleae J.G. Agardh, 1892 accepted as Nizymenia australis Sonder, 1855
• Anatheca dentata (Suhr) Papenfuss, 1940 accepted as Sarcodia dentata (Suhr) R.E. Norris, 1987
• Anatheca dichotoma M.A. Howe, 1911 accepted as Sarcodiotheca dichotoma (M.A. Howe) E.Y. Dawson, 1944
• Anatheca elongata Setchell & N.L. Gardner, 1924 accepted as Sarcodiotheca elongata (Setchell & N.L. Gardner) Setchell, 1944
• Anatheca furcata Setchell & N.L. Gardner, 1903 accepted as Sarcodiotheca furcata (Setchell & N.L. Gardner) Kylin, 1925
• Anatheca montagnei F. Schmitz, 1896
• Andersoniella farlowii F. Schmitz
• Antrocentrum nigrescens (Harvey) G.T. Kraft & Min-Thein, 1983