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. Acetabularia acetabulum (Linnaeus) P.C.Silva, 1952 represented as Acetabularia acetabulum (Linnaeus) P.C. Silva, 1952 (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)
Acrochaete N.Pringsheim, 1862 accepted as Ulvella P.L.Crouan & H.M.Crouan, 1859 (basis of record)
Acrochaetiaceae Melchior, 1954 (basis of record)
Acrochaetiales (basis of record)
Acrochaetium Nägeli, 1858 (basis of record)
Acrochaetium alariae (Jónsson) Bornet, 1904 (basis of record)
Acrochaetium balticum (Rosenvinge) Aleem & Schulz, 1952 (basis of record)
Acrochaetium barbadensis (Vickers) Borgesen, 1915 (basis of record)
Acrochaetium battersianum Hamel, 1927 (basis of record)
Acrochaetium boergesenii Schiffner, 1931 (basis of record)
Acrochaetium brebneri (Batters) Hamel, 1928 (basis of record)
Acrochaetium canariense Børgesen, 1927 (basis of record)
Acrochaetium catenulatum M.Howe, 1914 (basis of record)
Acrochaetium cheminii Feldmann, 1954 (basis of record)
Acrochaetium corymbiferum (Thuret) Batters, 1902 accepted as Colaconema corymbiferum (Thuret) Alongi, Cormaci & G.Furnari, 2017 (basis of record)
Acrochaetium crassipes (Børgesen) Børgesen, 1915 (basis of record)
Acrochaetium cymopoliae Børgesen, 1927 (basis of record)
Acrochaetium cytophagum (Rosenvinge) Hamel, 1927 (basis of record)
Acrochaetium densum (K.M.Drew) Papenfuss, 1945 accepted as Acrochaetium catenulatum M.Howe, 1914 (basis of record)
Acrochaetium duboscqii Feldmann, 1935 (basis of record)
Acrochaetium dumontiae (Rosenvinge) Hamel, 1927 (basis of record)
Acrochaetium emergens (Rosenvinge) Weber Bosse, 1921 accepted as Colaconema emergens (Rosenvinge) R.Nielsen, 1994 (basis of record)
Acrochaetium endozoicum (Darbishire) Batters, 1902 (basis of record)
Acrochaetium extensum Ercegovic, 1957 (basis of record)
Acrochaetium gynandrum (Rosenvinge) Hamel, 1927 accepted as Colaconema gynandrum (Rosenvinge) R.Nielsen, 1994 (basis of record)
Acrochaetium hauckii Schiffner, 1916 (basis of record)
Acrochaetium humile (Rosenvinge) Børgesen, 1915 (basis of record)
Acrochaetium immersum (Rosenvinge) Hamel, 1927 (basis of record)
Acrochaetium inclusum (Levring) Papenfuss, 1945 (basis of record)
Acrochaetium incrassatum Ercegovic, 1957 (basis of record)
Acrochaetium kylinii Hamel, 1927 (basis of record)
Acrochaetium lenormandii (Suhr ex Kützing) Nägeli, 1862 accepted as Acrochaetium secundatum (Lyngbye) Nägeli, 1858 (basis of record)
Acrochaetium leptonema (Rosenvinge) Børgesen, 1915 accepted as Colaconema leptonema (Rosenvinge) Alongi, Cormaci & G.Furnari, 2017 (basis of record)
Acrochaetium liagorae Børgesen, 1915 (basis of record)
Acrochaetium lorrain-smithiae (Lyle) L.Newton, 1931 (basis of record)
Acrochaetium macula (Rosenvinge) Hamel, 1927 (basis of record)
Acrochaetium mediterraneum (Levring) Athanasiadis, 2003 (basis of record)
Acrochaetium microfilum C.-C.Jao, 1936 (basis of record)
Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli, 1858 (basis of record)
Acrochaetium minutissimum (Shur) Nägeli, 1861 accepted as Acrochaetium minutissimum Nägeli, 1862 accepted as Acrochaetium minutum (Suhr) Hamel, 1927 (basis of record)
Acrochaetium minutum (Suhr) Hamel, 1927 (basis of record)
Acrochaetium mirabilis (Suhr) Nägeli, 1862 (basis of record)
Acrochaetium molinieri Coppejans & Boudouresque, 1976 (basis of record)
Acrochaetium moniliforme (Rosenvinge) Børgesen, 1915 (basis of record)
Acrochaetium nitophyllii (Levring) Papenfuss, 1945 (basis of record)
Acrochaetium pallens (Zanardini) Nägeli, 1862 (basis of record)
Acrochaetium parvulum (Kylin) Hoyt, 1920 (basis of record)
Acrochaetium pulchellum Børgesen, 1915 (basis of record)
Acrochaetium radiatum C.-C.Jao, 1936 accepted as Acrochaetium humile (Rosenvinge) Børgesen, 1915 (basis of record)
Acrochaetium reductum (Rosenvinge) Hamel, 1927 (basis of record)
Acrochaetium robustum Børgesen, 1915 accepted as Colaconema robustum (Børgesen) Huisman & Woelkerling, 2018 (basis of record)
Acrochaetium rosulata (Rosenvinge) Papenfuss accepted as Acrochaetium rosulatum (Rosenvinge) Papenfuss, 1945 accepted as Kylinia rosulata Rosenvinge, 1909 (basis of record)
Acrochaetium sanctae-mariae (Darbishire) Hamel, 1927 (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 seiriolanum (Gibson) Rosenvinge, 1924 accepted as Acrochaetium seiriolanum (Harvey-Gibson) Hamel, 1927 (basis of record)
Acrochaetium sparsum (Harvey) Nägeli, 1862 (basis of record)
Acrochaetium stilophorae (Levring) Kylin, 1944 (basis of record)
Acrochaetium subpinnatum Bornet ex Hamel, 1927 (basis of record)
Acrochaetium subseriatum Børgesen, 1932 (basis of record)
Acrochaetium subtilissimum (Kützing) Hamel, 1927 accepted as Colaconema subtilissimum (Kützing) Alongi, Cormaci & G.Furnari, 2017 (basis of record)
Acrochaetium trifilum (Buffham) Batters, 1902 (basis of record)
Acrochaetium unifilum C.-C.Jao, 1936 (basis of record)
Acrochaetium virgatulum (Harvey) Batters, 1902 accepted as Acrochaetium secundatum (Lyngbye) Nägeli, 1858 (basis of record)
Acrocytis Rosenvinge, 1933 (basis of record)
Acrocytis groenlandica Rosenvinge (basis of record)
Acrodiscus Zanardini, 1869 (basis of record)
Acrodiscus vidovichii (Meneghini) Zanardini, 1868 (basis of record)
Acrosiphonia J.Agardh, 1846 (basis of record)
Acrosiphonia arcta (Dillwyn) Gain, 1912 (basis of record)
Acrosiphonia flagellata Kjellman, 1893 (basis of record)
Acrosiphonia grandis Kjelmann, 1893 (basis of record)
Acrosiphonia incurva Kjellman, 1893 (basis of record)
Acrosiphonia sonderi (Kützing) Kornmann, 1962 (basis of record)
Acrosiphonia spinescens (Kützing) Kjellman, 1893 (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)
Acrospongium Schiffner, 1916 (basis of record)
Acrospongium ralfsioides Schiffner, 1916 (basis of record)
Acrosymphytaceae S.C.Lindstrom, 1987 (basis of record)
Acrosymphyton Sjöstedt, 1926 (basis of record)
Acrosymphyton purpuriferum (J.Agardh) G.Sjöstedt, 1926 (basis of record)
Acrosymphyton taylorii I.A.Abbott, 1962 (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)
Adriogloia Ercegovic, 1955 (basis of record)
Adriogloia adriatica Ercegovic, 1955 (basis of record)
Aeodes J.Agardh, 1876 (basis of record)
Aeodes marginata (Roussel) F.Schmitz, 1894 accepted as Felicinia marginata (Roussel) Manghisi, Le Gall, Ribera, Gargiulo & Morabito, 2014 (basis of record)
Agardhiella F.Schmitz, 1897 (basis of record)