Acanthophora J.V.Lamouroux, 1813 (basis of record)
Acanthophora muscoides (Linnaeus) Bory de Saint-Vincent, 1828 (basis of record)
Acanthophora nayadiformis (Delile) Papenfuss, 1968 (additional source)
Acetabularia J.V.Lamouroux, 1812 (basis of record)
Acetabularia subg. Acicularia caliculus J.V. Lamouroux, 1824 represented as Acetabularia caliculus J.V.Lamouroux, 1824 (basis of record)
Acinetospora Bornet, 1891 (basis of record)
Acinetospora crinita (Carmichael) Sauvageau, 1899 (basis of record)
Acrochaetiaceae Melchior, 1954 (basis of record)
Acrochaetiales (basis of record)
Acrochaetium Nägeli, 1858 (basis of record)
Acrochaetium balticum (Rosenvinge) Aleem & Schulz, 1952 (basis of record)
Acrochaetium catenulatum M.Howe, 1914 (basis of record)
Acrochaetium codicolum Børgesen, 1927 accepted as Acrochaetium codicola Børgesen, 1927 accepted as Colaconema codicola (Børgesen) Stegenga, J.J.Bolton & R.J.Anderson, 1997 (basis of record)
Acrochaetium densum (K.M.Drew) Papenfuss, 1945 accepted as Acrochaetium catenulatum M.Howe, 1914 (basis of record)
Acrochaetium kylinii Hamel, 1927 (basis of record)
Acrochaetium leptonema (Rosenvinge) Børgesen, 1915 accepted as Colaconema leptonema (Rosenvinge) Alongi, Cormaci & G.Furnari, 2017 (basis of record)
Acrochaetium mediterraneum (Levring) Athanasiadis, 2003 (basis of record)
Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli, 1858 (basis of record)
Acrochaetium moniliforme (Rosenvinge) Børgesen, 1915 (basis of record)
Acrochaetium robustum Børgesen, 1915 accepted as Colaconema robustum (Børgesen) Huisman & Woelkerling, 2018 (basis of record)
Acrochaetium savianum (Meneghini) Nägeli, 1862 accepted as Colaconema savianum (Meneghini) R.Nielsen, 1994 (basis of record)
Acrochaetium secundatum (Lyngbye) Nägeli, 1858 (basis of record)
Acrochaetium subpinnatum Bornet ex Hamel, 1927 (basis of record)
Acrochaetium subseriatum Børgesen, 1932 (basis of record)
Acrosorium Zanardini ex Kützing, 1869 (basis of record)
Acrosorium venulosum (Zanardini) Kylin, 1924 (basis of record)
Acrosymphytaceae S.C.Lindstrom, 1987 (basis of record)
Acrothamnion J.Agardh, 1892 (basis of record)
Acrothamnion preissii (Sonder) E.M.Wollaston, 1968 (additional source)
Acrothrix Kylin, 1907 (basis of record)
Acrothrix gracilis Kylin, 1907 (basis of record)
Agardhiella F.Schmitz, 1897 (basis of record)
Agardhiella subulata (C.Agardh) Kraft & M.J.Wynne, 1979 (additional source)
Aglaothamnion Feldmann-Mazoyer, 1941 (basis of record)
Aglaothamnion feldmanniae Halos, 1965 (basis of record)
Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer, 1941 (basis of record)
Ahnfeltiopsis P.C.Silva & DeCew, 1992 (basis of record)
Ahnfeltiopsis devoniensis (Greville) P.C.Silva & DeCew, 1992 (basis of record)
Alaria Greville, 1830 (basis of record)
Alaria esculenta (Linnaeus) Greville, 1830 (basis of record)
Alariaceae Setchell & Gardner, 1925 (basis of record)
Amphiroa J.V.Lamouroux, 1812 (basis of record)
Amphiroa rigida J.V.Lamouroux, 1816 (basis of record)
Anadyomenaceae Kützing, 1843 (basis of record)
Anadyomene J.V.Lamouroux, 1812 (basis of record)
Anotrichium Nägeli, 1862 (basis of record)
Anotrichium furcellatum (J.Agardh) Baldock, 1976 (basis of record)
Antithamnion Nägeli, 1847 (basis of record)
Antithamnion cruciatum (C.Agardh) Nägeli, 1847 (basis of record)
Antithamnion densum (Suhr) M.Howe, 1914 (basis of record)
Antithamnion diminuatum Wollaston, 1968 (basis of record)
Antithamnion subg. Pteroton amphigeneum A.J.K.Millar, 1990 represented as Antithamnion amphigeneum A.Millar, 1990 (basis of record)
Antithamnion subg. Pteroton pectinatum (Montagne) Brauner ex Athanasiadis & Tittley represented as Antithamnion pectinatum (Montagne) Brauner, 1994 (basis of record)
Antithamnionella Lyle, 1922 (basis of record)
Antithamnionella boergesenii (Cormaci & G.Furnari) Athanasiadis, 1996 (basis of record)
Antithamnionella elegans (Berthold) J.H.Price & D.M.John, 1986 (basis of record)
Antithamnionella spirographidis (Schiffner) E.M.Wollaston, 1968 (basis of record)
Apoglossum J.Agardh, 1898 (basis of record)
Apoglossum gregarium (E.Y.Dawson) M.J.Wynne, 1985 accepted as Phrix spatulata (E.Y.Dawson) M.J.Wynne, M.Kamiya & J.A.West, 2018 (additional source)
Ascophyllum Stackhouse, 1809 (basis of record)
Ascophyllum nodosum (Linnaeus) Le Jolis, 1863 (basis of record)
Asparagopsis Montagne, 1840 (basis of record)
Asparagopsis armata Harvey, 1855 (additional source)
Asparagopsis taxiformis (Delile) Trevisan de Saint-Léon, 1845 (additional source)
Asperococcus J.V.Lamouroux, 1813 (basis of record)
Asperococcus compressus A.W.Griffiths ex W.J.Hooker, 1833 accepted as Asperococcus ensiformis (Delle Chiaje) M.J.Wynne, 2003 (basis of record)
Asperococcus scaber Kuckuck, 1899 (basis of record)
Audouinella Bory de Saint-Vincent, 1823 (basis of record)
Avrainvillea Decaisne, 1842 (basis of record)
Bangia Lyngbye, 1819 (basis of record)
Bangia atropurpurea (Mertens ex Roth) C.Agardh, 1824 (basis of record)
Bangiaceae Duby, 1830 (basis of record)
Blastophysa Reinke, 1889 (basis of record)
Blastophysa rhizopus Reinke, 1889 (basis of record)
Blidingia Kylin, 1947 (basis of record)
Blidingia marginata (J.Agardh) P.J.L.Dangeard ex Bliding, 1963 (basis of record)
Blidingia minima (Nägeli ex Kützing) Kylin, 1947 (basis of record)
Bolbocoleon Pringsheim, 1863 (basis of record)
Bolbocoleon piliferum Pringsheim, 1862 (basis of record)
Bonnemaisonia C.Agardh, 1822 (basis of record)
Bonnemaisonia asparagoides (Woodward) C.Agardh, 1822 (basis of record)
Bonnemaisonia hamifera Hariot, 1891 (basis of record)
Bonnemaisoniaceae Schmitz, 1892 (basis of record)
Bonnemaisoniales (additional source)
Boodleaceae Børgesen, 1925 (basis of record)
Botryocladia (J.Agardh) Kylin, 1931 (basis of record)
Botryocladia madagascariensis G.Feldmann, 1945 (additional source)
Botrytella Bory de Saint-Vincent, 1822 (basis of record)
Botrytella micromora Bory, 1822 (basis of record)
Botrytella reinboldii (Reinke) Kornmann & Sahling, 1988 (basis of record)
Bryopsidaceae Bory de Saint-Vincent, 1829 (basis of record)
Bryopsis J.V.Lamouroux, 1809 (basis of record)
Bryopsis pennata J.V.Lamouroux, 1809 (basis of record)
Callithamnion Lyngbye, 1819 (basis of record)
Callithamnion corymbosum (Smith) Lyngbye, 1819 (basis of record)
Callithamnion tetragonum (Stackhouse) S.F.Gray, 1821 (basis of record)
Caulacanthaceae Kützing, 1843 (basis of record)
Caulacanthus Kützing, 1843 (basis of record)
Caulacanthus ustulatus (Turner) Kützing, 1843 (additional source)
Caulerpa J.V.Lamouroux, 1809 (basis of record)