Acrochaete heteroclada J.A.Correa & R.Nielsen, 1988 accepted as Ulvella heteroclada (Correa & R.Nielsen)R.Nielsen, C.J.O'Kelly & B.Wysor, 2013 (additional source)
Acrochaete leptochaete (Huber) R.Nielsen, 1983 accepted as Ulvella leptochaete (Huber) R.Nielsen, C.J.O'Kelly & B.Wysor, 2013 (additional source)
Acrochaete operculata J.A.Correa & R.Nielsen, 1988 accepted as Ulvella operculata (Correa & R.Nielsen) R.Nielsen, C.J.O'Kelly & B.Wysor, 2013 (additional source)
Acrochaete repens Pringsheim, 1862 accepted as Ulvella repens (Pringsheim) R.Nielsen, C.J.O'Kelly & B.Wysor, 2013 (additional source)
Acrochaete viridis (Reinke) R.Nielsen, 1979 accepted as Ulvella viridis (Reinke) R.Nielsen, C.J.O'Kelly & B.Wysor, 2013 (additional source)
Acrochaete wittrockii (Wille) R.Nielsen, 1983 accepted as Ulvella wittrockii (Wille) R.Nielsen, C.J.O'Kelly & B.Wysor, 2013 (additional source)
Acrosiphonia sonderi (Kützing) Kornmann, 1962 (additional source)
Acrothrix gracilis Kylin, 1907 (additional source)
Agardhiella subulata (C.Agardh) Kraft & M.J.Wynne, 1979 (additional source)
Agarum clathratum Dumortier, 1822 (additional source)
Aglaothamnion halliae (Collins) Aponte, D.L.Ballantine & J.N.Norris, 1997 (basis of record)
Ahnfeltia plicata (Hudson) E.M.Fries, 1836 (additional source)
Alaria esculenta (Linnaeus) Greville, 1830 (additional source)
Antithamnion cruciatum (C.Agardh) Nägeli, 1847 (additional source)
Antithamnionella floccosa (O.F.Müller) Whittick, 1980 (additional source)
Arthrocladia villosa (Hudson) Duby, 1830 (additional source)
Ascocyclus distromaticus W.R.Taylor, 1937 accepted as Phycocelis foecunda Strömfelt, 1888 accepted as Myrionema foecundum (Strömfelt) Sauvageau, 1897 (basis of record)
Ascocyclus orbicularis (J.Agardh) Kjellman, 1890 (additional source)
Ascophyllum nodosum (Linnaeus) Le Jolis, 1863 (additional source)
Asperococcus fistulosus (Hudson) W.J.Hooker, 1833 (additional source)
Audouinella alariae (Jónsson) Woelkerling, 1973 accepted as Acrochaetium alariae (Jónsson) Bornet, 1904 (additional source)
Audouinella dasyae (Collins) Woelkerling, 1973 accepted as Colaconema dasyae (Collins) Stegenga, I.Mol, Prud'homme & Lokhorst, 1997 (basis of record)
Audouinella daviesii (Dillwyn) Woelkerling, 1971 accepted as Colaconema daviesii (Dillwyn) Stegenga, 1985 (basis of record)
Audouinella efflorescens (J.Agardh) Papenfuss, 1945 accepted as Grania efflorescens (J.Agardh) Kylin, 1944 (additional source)
Audouinella humilis (Rosenv.) Garbary accepted as Acrochaetium humile (Rosenvinge) Børgesen, 1915 (basis of record)
Audouinella membranacea (Magnus) Papenfuss, 1945 accepted as Rubrointrusa membranacea (Magnus) S.L.Clayden & G.W.Saunders, 2010 (additional source)
Audouinella microscopica (Nägeli ex Kützing) Woelkerling, 1971 accepted as Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli, 1858 (basis of record)
Audouinella polyides (Rosenv.) Garbary accepted as Audouinella polyidis (Rosenvinge) Garbary, 1979 accepted as Helminthora divaricata (C.Agardh) J.Agardh, 1852 (basis of record)
Audouinella purpurea (Lightfoot) Woelkerling, 1973 accepted as Rhodochorton purpureum (Lightfoot) Rosenvinge, 1900 (additional source)
Audouinella saviana (Meneghini) Woelkerling, 1973 accepted as Colaconema savianum (Meneghini) R.Nielsen, 1994 (basis of record)
Audouinella secundata (Lyngbye) P.S.Dixon, 1976 accepted as Acrochaetium secundatum (Lyngbye) Nägeli, 1858 (basis of record)
Audouinella virgatula (Harvey) P.S.Dixon, 1976 accepted as Acrochaetium secundatum (Lyngbye) Nägeli, 1858 (basis of record)
Bangia fuscopurpurea (Dillwyn) Lyngbye, 1819 (basis of record)
Blastophysa rhizopus Reinke, 1889 (additional source)
Blidingia marginata (J.Agardh) P.J.L.Dangeard ex Bliding, 1963 (additional source)
Blidingia minima (Nägeli ex Kützing) Kylin, 1947 (additional source)
Blidingia ramifera (Bliding) Garbary & L.B.Barkhouse, 1987 (additional source)
Bolbocoleon piliferum Pringsheim, 1862 (additional source)
Bonnemaisonia hamifera Hariot, 1891 (additional source)
Bostrychia radicans (Montagne) Montagne, 1842 (basis of record)
Botrytella micromora Bory, 1822 (additional source)
Bryopsis hypnoides J.V.Lamouroux, 1809 (additional source)
Bryopsis plumosa (Hudson) C.Agardh, 1823 (additional source)
Callithamnion corymbosum (Smith) Lyngbye, 1819 (additional source)
Callithamnion tetragonum (Stackhouse) S.F.Gray, 1821 (additional source)
Callocolax fungiformis Kylin, 1925 (basis of record)
Callophyllis cristata (C.Agardh) Kützing, 1849 accepted as Euthora cristata (C.Agardh) J.Agardh, 1847 (additional source)
Capsosiphon fulvescens (C.Agardh) Setchell & N.L.Gardner, 1920 (additional source)
Capsosiphon groenlandicus (J.Agardh) K.L.Vinogradova, 1974 accepted as Pseudothrix groenlandica (J.Agardh) Hanic & S.C.Lindstrom, 2008 (additional source)
Ceramium cimbricum H.E.Petersen, 1924 (additional source)
Ceramium circinatum (Kützing) J.Agardh, 1851 (additional source)
Ceramium deslongchampsii Chauvin ex Duby, 1830 (additional source)
Ceramium diaphanum (Lightfoot) Roth, 1806 (additional source)
Ceramium elegans (Roth) Ducluzeau, 1805 accepted as Ceramium siliquosum var. elegans (Roth) G.Furnari, 1999 (basis of record)
Ceramium rubrum C.Agardh, 1811 accepted as Ceramium virgatum Roth, 1797 (additional source)
Ceramium strictum (Kützing) Rabenhorst, 1847 accepted as Ceramium deslongchampsii Chauvin ex Duby, 1830 (additional source)
Ceratocolax hartzii Rosenvinge, 1898 accepted as Coccotylus hartzii (Rosenvinge) Le Gall & G.W.Saunders, 2010 (additional source)
Chaetomorpha aerea (Dillwyn) Kützing, 1849 (additional source)
Chaetomorpha brachygona Harvey, 1858 (basis of record)
Chaetomorpha capillaris (Kützing) Børgesen, 1925 (basis of record)
Chaetomorpha linum (O.F.Müller) Kützing, 1845 (additional source)
Chaetomorpha melagonium (F.Weber & D.Mohr) Kützing, 1845 (additional source)
Chaetomorpha minima Collins & Hervey, 1917 (basis of record)
Chaetomorpha picquotiana Montagne ex Kützing, 1849 (basis of record)
Champia parvula (C.Agardh) Harvey, 1853 (additional source)
Chilionema reptans (P.L.Crouan & H.M.Crouan) Sauvageau, 1897 accepted as Asperococcus fistulosus (Hudson) W.J.Hooker, 1833 (additional source)
Chondria baileyana (Montagne) Harvey, 1853 (basis of record)
Chondrus crispus Stackhouse, 1797 (additional source)
Chorda filum (Linnaeus) Stackhouse, 1797 (additional source)
Chorda tomentosa Lyngbye, 1819 accepted as Halosiphon tomentosus (Lyngbye) Jaasund, 1957 (additional source)
Chordaria flagelliformis (O.F.Müller) C.Agardh, 1817 (additional source)
Choreocolax polysiphoniae Reinsch, 1875 (additional source)
Chroodactylon ornatum (C.Agardh) Basson, 1979 (additional source)
Cladophora albida (Nees) Kutzing, 1843 (additional source)
Cladophora dalmatica Kützing, 1843 (additional source)
Cladophora globulina (Kützing) Kützing, 1845 (additional source)
Cladophora laetevirens (Dillwyn) Kützing, 1843 (additional source)
Cladophora liniformis Kützing, 1849 (additional source)
Cladophora pygmaea Reinke, 1888 accepted as Lychaete pygmaea (Reinke) M.J.Wynne, 2017 (additional source)
Cladophora ruchingeri (C.Agardh) Kützing, 1845 (additional source)
Cladophora rupestris (Linnaeus) Kützing, 1843 (additional source)
Cladophora sericea (Hudson) Kützing, 1843 (additional source)
Cladophora vagabunda (Linnaeus) Hoek, 1963 (additional source)
Cladosiphon zosterae (J.Agardh) Kylin, 1940 (additional source)
Cladostephus spongiosus (Hudson) C.Agardh, 1817 (additional source)
Clathromorphum circumscriptum (Strömfelt) Foslie, 1898 (additional source)
Clathromorphum compactum (Kjellman) Foslie, 1898 (additional source)
Coccotylus truncatus (Pallas) M.J.Wynne & J.N.Heine, 1992 (additional source)
Codium fragile (Suringar) Hariot, 1889 (additional source)
Coilodesme bulligera Strömfelt, 1886 (additional source)
Colpomenia peregrina Sauvageau, 1927 (additional source)
Corallina officinalis Linnaeus, 1758 (additional source)
Cystoclonium purpureum (Hudson) Batters, 1902 (additional source)
Dasya baillouviana (S.G.Gmelin) Montagne, 1841 accepted as Dasya pedicellata (C.Agardh) C.Agardh, 1824 (additional source)
Delamarea attenuata (Kjellman) Rosenvinge, 1893 (additional source)
Derbesia marina (Lyngbye) Solier, 1846 (additional source)
Dermatolithon pustulatum (J.V.Lamouroux) Foslie, 1898 accepted as Titanoderma pustulatum (J.V.Lamouroux) Nägeli, 1858 (basis of record)
Desmarestia aculeata (Linnaeus) J.V.Lamouroux, 1813 (additional source)
Desmarestia viridis (O.F.Müller) J.V.Lamouroux, 1813 (additional source)
Devaleraea ramentacea (Linnaeus) Guiry, 1982 (additional source)