Acanthophora J.V.Lamouroux, 1813 (basis of record)
Acanthophora muscoides (Linnaeus) Bory de Saint-Vincent, 1828 (basis of record)
Acetabularia J.V.Lamouroux, 1812 (basis of record)
Acetabularia parvula Solms-Laubach, 1895 accepted as Parvocaulis parvulus (Solms-Laubach) S.Berger, Fettweiss, Gleissberg, Liddle, U.Richter, Sawitzky & Zuccarello, 2003 (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 catenulatum M.Howe, 1914 (basis of record)
Acrochaetium densum (K.M.Drew) Papenfuss, 1945 accepted as Acrochaetium catenulatum M.Howe, 1914 (basis of record)
Acrochaetium humile (Rosenvinge) Børgesen, 1915 (basis of record)
Acrochaetium macula (Rosenvinge) Hamel, 1927 (basis of record)
Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli, 1858 (basis of record)
Acrochaetium parvulum (Kylin) Hoyt, 1920 (basis of record)
Acrochaetium robustum Børgesen, 1915 accepted as Colaconema robustum (Børgesen) Huisman & Woelkerling, 2018 (basis of record)
Acrochaetium secundatum (Lyngbye) Nägeli, 1858 (basis of record)
Acrosiphonia J.Agardh, 1846 (basis of record)
Acrosiphonia arcta (Dillwyn) Gain, 1912 (basis of record)
Acrosiphoniaceae S. Jónsson, 1959 (additional source)
Acrosorium Zanardini ex Kützing, 1869 (basis of record)
Acrosorium venulosum (Zanardini) Kylin, 1924 (basis of record)
Acrothrix Kylin, 1907 (basis of record)
Aglaothamnion Feldmann-Mazoyer, 1941 (basis of record)
Ahnfeltia Fries, 1836 (basis of record)
Ahnfeltiaceae Maggs & Pueschel, 1989 (basis of record)
Ahnfeltiales (basis of record)
Ahnfeltiopsis P.C.Silva & DeCew, 1992 (basis of record)
Alariaceae Setchell & Gardner, 1925 (basis of record)
Amphiroa J.V.Lamouroux, 1812 (basis of record)
Amphiroa beauvoisii J.V.Lamouroux, 1816 (basis of record)
Amphiroa fragilissima (Linnaeus) 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 tenue (C.Agardh) Nägeli, 1862 (basis of record)
Antithamnion Nägeli, 1847 (basis of record)
Antithamnion cruciatum (C.Agardh) Nägeli, 1847 (basis of record)
Antithamnionella Lyle, 1922 (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)
Asparagopsis Montagne, 1840 (basis of record)
Asparagopsis taxiformis (Delile) Trevisan de Saint-Léon, 1845 (additional source)
Asteronema Delépine & Asensi, 1975 (basis of record)
Audouinella Bory de Saint-Vincent, 1823 (basis of record)
Bangia Lyngbye, 1819 (basis of record)
Bangiaceae Duby, 1830 (basis of record)
Blidingia Kylin, 1947 (basis of record)
Blidingia minima (Nägeli ex Kützing) Kylin, 1947 (basis of record)
Bonnemaisonia C.Agardh, 1822 (basis of record)
Bonnemaisonia hamifera Hariot, 1891 (basis of record)
Bonnemaisoniaceae Schmitz, 1892 (basis of record)
Bonnemaisoniales (additional source)
Boodlea G.Murray & De Toni, 1889 (basis of record)
Boodlea struveoides M.Howe, 1918 (basis of record)
Boodleaceae Børgesen, 1925 (basis of record)
Bostrychia Montagne, 1842 (basis of record)
Botryocladia (J.Agardh) Kylin, 1931 (basis of record)
Botryocladia pyriformis (Børgesen) Kylin, 1931 (basis of record)
Botrytella Bory de Saint-Vincent, 1822 (basis of record)
Bryopsidaceae Bory de Saint-Vincent, 1829 (basis of record)
Bryopsis J.V.Lamouroux, 1809 (basis of record)
Bryopsis hypnoides 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)
Callophyllis Kützing, 1843 (basis of record)
Catenella Greville, 1830 (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)
Caulerpa cupressoides (Vahl) C.Agardh, 1817 (basis of record)
Caulerpa mexicana Sonder ex Kützing, 1849 (additional source)
Caulerpa peltata J.V.Lamouroux, 1809 accepted as Caulerpa chemnitzia (Esper) J.V.Lamouroux, 1809 (basis of record)
Caulerpa prolifera (Forsskål) J.V.Lamouroux, 1809 (basis of record)
Caulerpa racemosa (Forsskål) J.Agardh, 1873 (additional source)
Caulerpa sertularioides (S.G.Gmelin) M.Howe, 1905 (basis of record)
Caulerpa taxifolia (M.Vahl) C.Agardh, 1817 (additional source)
Caulerpa webbiana Montagne, 1837 (basis of record)
Caulerpaceae Kützing, 1843 (basis of record)
Centroceras Kützing, 1842 '1841' (basis of record)
Centroceras clavulatum (C.Agardh) Montagne, 1846 (basis of record)
Ceramiaceae Dumortier, 1822 (basis of record)
Ceramiales (basis of record)
Ceramium Roth, 1797 (basis of record)
Ceramium comptum Børgesen, 1924 accepted as Yoneshiguea compta (Børgesen) Barros-Barreto, Maggs & M.A.Jaramillo, 2023 (basis of record)
Ceramium diaphanum (Lightfoot) Roth, 1806 (basis of record)
Ceramium flaccidum (Harvey ex Kützing) Ardissone, 1871 accepted as Gayliella flaccida (Harvey ex Kützing) T.O.Cho & L.J.McIvor, 2008 (basis of record)
Ceramium tenerrimum (G.Martens) Okamura, 1921 accepted as Pseudoceramium tenerrimum (G.Martens) Barros-Barreto & Maggs, 2023 (basis of record)
Chaetomorpha Kützing, 1845 (basis of record)
Chaetomorpha aerea (Dillwyn) Kützing, 1849 (basis of record)
Chaetomorpha antennina (Bory) Kützing, 1847 (basis of record)
Chaetomorpha crassa (C.Agardh) Kützing, 1845 (basis of record)
Chaetomorpha linum (O.F.Müller) Kützing, 1845 (basis of record)
Chaetophoraceae Greville, 1824 (basis of record)
Champia Desvaux, 1809 (basis of record)
Champia parvula (C.Agardh) Harvey, 1853 (basis of record)
Champiaceae Kützing, 1843 (basis of record)
Chondracanthus Kützing, 1843 (basis of record)