• Acanthophora muscoides (Linnaeus) Bory de Saint-Vincent, 1828
• Acanthophora nayadiformis (Delile) Papenfuss, 1968
• Acrodiscus vidovichii (Meneghini) Zanardini, 1868
• Acrosorium ciliolatum (Harvey) Kylin, 1924
• Acrosorium reptans (P.Crouan & H.Crouan) Kylin, 1924 accepted as Cryptopleura ramosa (Hudson) L.Newton, 1931
• Acrosorium venulosum (Zanardini) Kylin, 1924
• Acrosymphyton purpuriferum (J.Agardh) G.Sjöstedt, 1926
• Acrosymphyton taylorii I.A.Abbott, 1962
• Acrothamnion preissii (Sonder) E.M.Wollaston, 1968
• Aeodes marginata (Roussel) F.Schmitz, 1894 accepted as Felicinia marginata (Roussel) Manghisi, Le Gall, Ribera, Gargiulo & Morabito, 2014
• Agardhiella subulata (C.Agardh) Kraft & M.J.Wynne, 1979
• Agardhinula browneae (J.Agardh) De Toni, 1897
• Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N.Norris et Fredericq, 2018 accepted as Gracilaria vermiculophylla (Ohmi) Papenfuss, 1967
• Aglaothamnion bipinnatum (P.Crouan & H.Crouan) Feldmann & G.Feldmann, 1948
• Aglaothamnion byssoides (Arnott ex Harvey) C.F.Boudouresque & M.M.Perret-Boudouresque, 1987 accepted as Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer, 1941
• Aglaothamnion caudatum (J.Agardh) Feldmann-Mazoyer, 1941
• Aglaothamnion chadefaudii L'Hardy-Halos, 1984
• Aglaothamnion cordatum (Børgesen) Feldmann-Mazoyer, 1941
• Aglaothamnion diaphanum L'Hardy-Halos & Maggs, 1991
• Aglaothamnion fasciculatum (Harvey) Maggs & L'Hardy-Halos, 1993
• Aglaothamnion feldmanniae Halos, 1965
• Aglaothamnion gaillonii (P.L.Crouan & H.M.Crouan) Halos, 1965
• Aglaothamnion gallicum (Nägeli) Halos ex Ardré, 1970 accepted as Gaillona gallica (Nägeli) Athanasiadis, 2016
• Aglaothamnion halliae (Collins) Aponte, D.L.Ballantine & J.N.Norris, 1997
• Aglaothamnion hookeri (Dillwyn) Maggs & Hommersand, 1993 accepted as Gaillona hookeri (Dillwyn) Athanasiadis, 2016
• Aglaothamnion priceanum Maggs, Guiry & Rueness, 1991
• Aglaothamnion pseudobyssoides (P.Crouan & H.Crouan) Halos, 1965
• Aglaothamnion roseum (Roth) Maggs & L'Hardy-Halos, 1993 accepted as Gaillona rosea (Roth) Athanasiadis, 2016
• Aglaothamnion scopulorum (C.Agardh) Feldmann-Mazoyer, 1941
• Aglaothamnion sepositum (Gunnerus) Maggs & Hommersand, 1993 accepted as Gaillona seposita (Gunnerus) Athanasiadis, 2016
• Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer, 1941
• Aglaothamnion tripinnatum (C.Agardh) Feldmann-Mazoyer, 1941
• Aglaothamnion westbrookiae Rueness & L'Hardy-Halos, 1991 accepted as Aglaothamnion halliae (Collins) Aponte, D.L.Ballantine & J.N.Norris, 1997
• Ahnfeltiopsis devoniensis (Greville) P.C.Silva & DeCew, 1992
• Ahnfeltiopsis pusilla (Montagne) P.C.Silva & DeCew, 1992
• Aiolocolax pulchellus Pocock, 1956
• Alsidium corallinum C.Agardh, 1827
• Alsidium helminthochorton (Schwendimann) Kützing, 1843
• Anotrichium barbatum (C.Agardh) Nägeli, 1862
• Anotrichium furcellatum (J.Agardh) Baldock, 1976
• Anotrichium tenue (C.Agardh) Nägeli, 1862
• Antithamnion amphigeneum A.Millar, 1990
• Antithamnion antillanum Børgesen, 1917
• Antithamnion boreale (Gobi) Kjellman, 1883 accepted as Scagelothamnion pusillum (Ruprecht) Athanasiadis, 1996
• Antithamnion cladodermum (Zanardini) Hauck, 1883 accepted as Balliella cladoderma (Zanardini) Athanasiadis, 1987
• Antithamnion compactum (Grunow) Schiffner, 1944
• Antithamnion crispum (Ducluzeau) Thuret, 1863 accepted as Pterothamnion crispum (Ducluzeau) Nägeli, 1862
• Antithamnion cruciatum (C.Agardh) Nägeli, 1847
• Antithamnion decipiens (J.Agardh) Athanasiadis, 1996
• Antithamnion defectum Kylin, 1925
• Antithamnion densum (Suhr) M.Howe, 1914
• Antithamnion diminuatum Wollaston, 1968
• Antithamnion heterocladum Funk, 1955
• Antithamnion pectinatum (Montagne) Brauner, 1994
• Antithamnion piliferum Cormaci & G.Furnari, 1987
• Antithamnion tenuissimum (Hauck) Schiffner, 1915
• Antithamnion villosum (Kützing) Athanasiadis, 1993
• Antithamnionella boergesenii (Cormaci & G.Furnari) Athanasiadis, 1996
• Antithamnionella elegans (Berthold) J.H.Price & D.M.John, 1986
• Antithamnionella floccosa (O.F.Müller) Whittick, 1980
• Antithamnionella spirographidis (Schiffner) E.M.Wollaston, 1968
• Antithamnionella ternifolia (Hooker f. & Harvey) Lyle, 1922
• Aphanocladia stichidiosa (Funk) Ardré, 1970 accepted as Lophurella stichidiosa (Funk) Díaz-Tapia, 2023
• Apoglossocolax pusillus Maggs & Hommersand, 1993
• 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
• Apoglossum ruscifolium (Turner) J.Agardh, 1898
• Arachnophyllum confervaceum (Meneghini) Zanardini, 1843
• Archestenogramma brasiliense (A.B.Joly) C.W.Schneider, Chengsupanimit & G.W.Saunders, 2011
• Asparagopsis armata Harvey, 1855
• Asparagopsis taxiformis (Delile) Trevisan de Saint-Léon, 1845
• Asterocolax erythroglossi Feldmann & G.Feldmann, 1951 accepted as Erythroglossum erythroglossi (Feldmann & G.Feldmann) Guiry & M.J.Wynne, 2021
• Asteromenia peltata (W.R.Taylor) Huisman & A.J.K.Millar, 1996
• Atractophora hypnoides P.Crouan & H.Crouan, 1848
• Austrokallymenia schizophylla (J.Agardh) G.W.Saunders, 2017
• Balliella cladoderma (Zanardini) Athanasiadis, 1987
• Beckerella dentata (Kützing) Athanasiadis, 2016 accepted as Ptilophora dentata (Kützing) Alongi, Cormaci & Furnari, 2020
• Beckerella mediterranea H.Huvé, 1962 accepted as Beckerella dentata (Kützing) Athanasiadis, 2016 accepted as Ptilophora dentata (Kützing) Alongi, Cormaci & Furnari, 2020
• Boergeseniella deludens (Falkenberg) Kylin, 1956
• Boergeseniella fruticulosa (Wulfen) Kylin, 1956 accepted as Vertebrata fruticulosa (Wulfen) Kuntze, 1891
• Boergeseniella martensiana (Kützing) Ardré, 1970 accepted as Vertebrata martensiana (Kützing) Piñeiro-Corbeira, Maggs & Díaz-Tapia, 2020
• Boergeseniella thuyoides (Harvey) Kylin, 1956 accepted as Vertebrata thuyoides (Harvey) Kuntze, 1891
• Bonnemaisonia asparagoides (Woodward) C.Agardh, 1822
• Bonnemaisonia clavata Hamel, 1930
• Bonnemaisonia hamifera Hariot, 1891
• Bornetia secundiflora (J.Agardh) Thuret, 1855
• Bostrychia scorpioides (Hudson) Montagne, 1842
• Botryocladia boergesenii Feldmann, 1935 accepted as Irvinea boergesenii (Feldmann) R.J.Wilkes, L.M.McIvor & Guiry, 2006
• Botryocladia botryoides (Wulfen) Feldmann, 1941
• Botryocladia bullosa (Levring) J.N.Norris & D.L.Ballantine, 1995
• Botryocladia chiajeana (Meneghini) Kylin, 1931 accepted as Irvinea chiajeana (Meneghini) Cormaci, Alongi & G.Furnari, 2012
• Botryocladia enteromorpha (Harvey) W.E.Schmidt, Lozada-Troche, D.L.Ballantine & Fredericq, 2017
• Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & A.Neto, 2006
• Botryocladia madagascariensis G.Feldmann, 1945
• Botryocladia microphysa (Hauck) Kylin, 1931
• Botryocladia occidentalis (Børgesen) Kylin, 1931
• Botryocladia pseudodichotoma (Farlow) Kylin, 1931
• Botryocladia pyriformis (Børgesen) Kylin, 1931
• Botryocladia wynnei Ballantine, 1985
• Branchioglossum prostratum C.W.Schneider, 1974
• Brongniartella byssoides (Goodenough & Woodward) F.Schmitz, 1893 accepted as Vertebrata byssoides (Goodenough & Woodward) Kuntze, 1891