• Acinetospora crinita (Carmichael) Sauvageau, 1899
• Acrocytis groenlandica Rosenvinge
• Acrospongium ralfsioides Schiffner, 1916
• Acrothrix gracilis Kylin, 1907
• Acrothrix neglecta (Batters) Kuckuck, 1929 (uncertain)
• Actinema scutellum Reinsch, 1875
• Actinomonas mirabilis Kent, 1880
• Adriogloia adriatica Ercegovic, 1955 (uncertain)
• Aglaozonia chilosa Falkenberg, 1879 accepted as Cutleria chilosa (Falkenberg) P.C.Silva, 1957
• Aglaozonia parvula (Greville) Zanardini, 1843 accepted as Cutleria multifida (Turner) Greville, 1830
• Alaria esculenta (Linnaeus) Greville, 1830
• Alaria grandifolia J.Agardh, 1872 accepted as Alaria esculenta (Linnaeus) Greville, 1830
• Alaria pylaiei (Bory) Greville, 1830
• Alaria pylaii (Bory de Saint-Vincent) Greville, 1830 accepted as Alaria pylaiei (Bory) Greville, 1830
• Anthophysa vegetans (O.F.Müller) F.Stein, 1878
• Apedinella radians (Lohmann) P.H.Campbell, 1973
• Arthrocladia villosa (Hudson) Duby, 1830
• Ascocyclus orbicularis (J.Agardh) Kjellman, 1890 (uncertain)
• Ascophyllum nodosum (Linnaeus) Le Jolis, 1863
• Ascophyllum nodosum f. scorpioides Hauck, 1883
• Ascophyllum nodosum var. scorpioides (Hauck) Reinke, 1889 accepted as Ascophyllum nodosum f. scorpioides Hauck, 1883
• Asperococcus bullosus J.V.Lamouroux, 1813
• Asperococcus compressus A.W.Griffiths ex W.J.Hooker, 1833 accepted as Asperococcus ensiformis (Delle Chiaje) M.J.Wynne, 2003
• Asperococcus ensiformis (Delle Chiaje) M.J.Wynne, 2003
• Asperococcus fistulosus (Hudson) W.J.Hooker, 1833
• Asperococcus scaber Kuckuck, 1899
• Asperococcus turneri (Dillwyn ex Smith) W.J.Hooker, 1833 accepted as Asperococcus bullosus J.V.Lamouroux, 1813
• Asterocladon rhodochortonoides (Børgesen) S.Uwai, C.Nagasato, T.Motomura & K.Kogame, 2005
• Asteronema rhodochortonoides (Børgesen) D.G.Müller & Parodi, 1994 accepted as Asterocladon rhodochortonoides (Børgesen) S.Uwai, C.Nagasato, T.Motomura & K.Kogame, 2005
• Aureococcus anophagefferens Hargraves & Sieburth, 1988
• Bachelotia antillarum (Grunow) Gerloff, 1959
• Battersia arctica (Harvey) Draisma, Prud'homme & H.Kawai, 2010
• Battersia mirabilis Reinke ex Batters, 1890
• Battersia plumigera (Holmes ex Hauck) Draisma, Prud'homme & H.Kawai, 2010
• Battersia racemosa (Greville) Draisma, Prud'homme & H.Kawai, 2010
• Bifurcaria bifurcata R.Ross, 1958
• Bitrichia chodatii (Reverdin) Chodat, 1926
• Botrytella micromora Bory, 1822
• Botrytella reinboldii (Reinke) Kornmann & Sahling, 1988
• Buffhamia speciosa Batters, 1895
• Canistrocarpus cervicornis (Kützing) De Paula & De Clerck, 2006
• Carpomitra costata (Stackhouse) Batters, 1902
• Carpomitra costata var. mediterranea (Feldmann) Feldmann, 1937
• Castagnea mediterranea (Kützing) Hauck accepted as Cladosiphon mediterraneus Kützing, 1843
• Chaetopteris plumosa (Lyngbye) Kützing, 1843
• Chattonella antiqua (Hada) C.Ono, 1980 accepted as Chattonella marina var. antiqua (Hada) Demura & Kawachi, 2009
• Chattonella marina (Subrahmanyan) Y.Hara & Chihara, 1982
• Chattonella marina var. antiqua (Hada) Demura & Kawachi, 2009
• Chattonella marina var. ovata (Y.Hara & Chihara) Demura & Kawachi, 2009
• Chattonella subsalsa B.Biecheler, 1936
• Chilionema foecundum (Strömfelt) R.L.Fletcher, 1987 accepted as Myrionema foecundum (Strömfelt) Sauvageau, 1897
• Chilionema hispanicum (Sauvageau) R.L.Fletcher, 1987
• Chilionema ocellatum (Kützing) Kornmann, 1953
• Chilionema reptans (P.L.Crouan & H.M.Crouan) Sauvageau, 1897 accepted as Asperococcus fistulosus (Hudson) W.J.Hooker, 1833
• Chlamydomyxa labyrinthuloides W.Archer, 1875
• Chorda filum (Linnaeus) Stackhouse, 1797
• Chorda tomentosa Lyngbye, 1819 accepted as Halosiphon tomentosus (Lyngbye) Jaasund, 1957
• Chordaria flagelliformis (O.F.Müller) C.Agardh, 1817
• Choristocarpus tenellus Zanardini, 1860
• Chromophysomonas bilacunosa (Takahashi) Preisig & Hibberd, 1982
• Chromophysomonas serrata (Nicholls) Preisig & D.J.Hibberd, 1982
• Chrysidiastrum catenatum Lauterborn, 1913
• Chrysococcus biporus Skuja, 1939
• Chrysococcus minutus (F.E.Fritsch) Nygaard, 1932
• Chrysococcus rufescens Klebs, 1892
• Chrysolykos planctonicus B.Mack, 1951
• Chrysosphaerella annulata J.Kristiansen & D.Tong, 1989
• Chrysosphaerella brevispina Korshikov, 1941
• Chrysosphaerella coronacircumspina Wujek & Kristiansen, 1977 accepted as Spiniferomonas coronacircumspina (Wujek & Kristiansen) K.H.Nicholls, 1984
• Chrysosphaerella patelliformis Takahashi & Hara, 1984
• Chrysosphaerella salina Birch-Andersen, 1973 accepted as Thaumatomastix salina (Birch-Andersen) Beech & Moestrup, 1986
• Chrysosphaerella triangulata I.M.Balonov, 1980
• Chrysosphaerella tripus Takahashi & Hara, 1984 accepted as Thaumatomastix tripus (Takahashi & Hara) Beech & Moestrup, 1986
• Chukchia endophytica (S.Lund) R.T.Wilce, P.M.Pedersen & S.Sekida, 2009
• Ciliophrys infusionum Cienkowski, 1876
• Cladosiphon contortus (Thuret) Kylin, 1940
• Cladosiphon cylindricus (Sauvageau) Kylin, 1940
• Cladosiphon irregularis (Sauvageau) Kylin, 1949
• Cladosiphon lubricus (Sauvageau) Kylin, 1940
• Cladosiphon mediterraneus Kützing, 1843
• Cladosiphon occidentalis Kylin, 1940
• Cladosiphon zosterae (J.Agardh) Kylin, 1940
• Cladostephus spongiosus (Hudson) C.Agardh, 1817
• Cladostephus spongiosus f. verticillatus (Lightfoot) Prud'homme van Reine, 1972
• Cladostephus verticillatus (Lightfoot) Lyngbye, 1819 accepted as Cladostephus spongiosus f. verticillatus (Lightfoot) Prud'homme van Reine, 1972
• Clathrodiscus mandoulii (Sauvageau) G.Hamel, 1935
• Climacosorus mediterraneus Sauvageau, 1933
• Coelocladia arctica Rosenvinge, 1893
• Coilodesme bulligera Strömfelt, 1886
• Colpomenia peregrina Sauvageau, 1927
• Colpomenia sinuosa (Mertens ex Roth) Derbès & Solier, 1851
• Compsonema gracile Kuckuck, 1899
• Compsonema microspongium (Batters) Kornmann, 1953
• Compsonema minutum (C.Agardh) Kuckuck, 1953
• Compsonema saxicola (Kuckuck) Kuckuck, 1953 (uncertain)
• Compsonema saxicolum (Kuckuck) Kuckuck accepted as Compsonema saxicola (Kuckuck) Kuckuck, 1953
• Corynophlaea crispa (Harvey) Kuckuck, 1929
• Corynophlaea cystophorae J.Agardh, 1882
• Corynophlaea flaccida (C.Agardh) Kützing, 1858
• Corynophlaea hamelii Feldmann, 1937