• Plumularia (Polysiphonia) Lendenfeld, 1885 accepted as Plumularia Lamarck, 1816
• Polysiphonia Greville, 1823
• Polysiphonia Hertwig, 1882 accepted as Exocoelactis Carlgren, 1925
• Polysiphonia Pomel, 1872 sensu Levinsen, 1893 accepted as Haliclona (Haliclona) Grant, 1836
• Polysiphonia abscissa J.D.Hooker & Harvey, 1845
• Polysiphonia abscissa f. microcarpa (J.D.Hooker & Harvey) Dickie (uncertain)
• Polysiphonia abscissoides Womersley, 1979
• Polysiphonia acanthina J.Agardh, 1863
• Polysiphonia acanthophora Harvey, 1844 accepted as Echinothamnion hookeri (Harvey) Kylin ex P.C.Silva, 1996
• Polysiphonia acanthophora Kützing, 1843 accepted as Neosiphonia sertularioides (Grateloup) K.W.Nam & P.J.Kang, 2012 accepted as Polysiphonia sertularioides (Grateloup) J.Agardh, 1863
• Polysiphonia acanthotricha Kützing, 1847 accepted as Polysiphonia flexella (C.Agardh) J.Agardh, 1842
• Polysiphonia acroblasta Kützing
• Polysiphonia acrolepta Zanardini ex A.De Toni
• Polysiphonia aculeata (C.Agardh) Fries, 1845 accepted as Leptosiphonia fibrillosa (Agardh) Savoie & G.W.Saunders, 2019
• Polysiphonia aculeifera Zanardini, 1847 accepted as Polysiphonia opaca (C.Agardh) Moris & De Notaris, 1839
• Polysiphonia acuminata N.L.Gardner, 1927
• Polysiphonia adamsiae Womersley, 1979
• Polysiphonia adriatica Schiffner, 1931 (uncertain)
• Polysiphonia adscendens (Bonnemaison) P.Crouan & H.Crouan (uncertain)
• Polysiphonia adscendens Meneghini, 1844 (uncertain)
• Polysiphonia adsendens Meneghini, 1844
• Polysiphonia adunca Kützing, 1849 accepted as Lophosiphonia reptabunda (Suhr) Kylin, 1956 accepted as Vertebrata reptabunda (Suhr) Díaz-Tapia & Maggs, 2017
• Polysiphonia affinis Moore, 1837 accepted as Vertebrata fucoides (Hudson) Kuntze, 1891
• Polysiphonia agardhiana Greville
• Polysiphonia aggregata Segi, 1944 accepted as Neosiphonia savatieri (Hariot) M.S.Kim & I.K.Lee, 1999 accepted as Melanothamnus savatieri (Hariot) Díaz-Tapia & Maggs, 2017
• Polysiphonia akkeshiensis Segi, 1951 accepted as Melanothamnus akkeshiensis (Segi) A.M.Saunders & G.W.Saunders, 2019
• Polysiphonia allochroa (Roth) Duby, 1830
• Polysiphonia amentacea (C.Agardh) Montagne
• Polysiphonia americana Reinsch (uncertain)
• Polysiphonia amethystea Kützing (uncertain)
• Polysiphonia amethystea f. crispa Suringar (uncertain)
• Polysiphonia amoena Sonder, 1855 accepted as Polysiphonia isogona Harvey, 1855
• Polysiphonia amphibia Harvey
• Polysiphonia amphibolis Womersley, 1979
• Polysiphonia amplacapilli B.Kim & M.S.Kim, 2014 accepted as Kapraunia amplacapilli (B.Kim & M.S.Kim) Savoie & G.W.Saunders, 2019
• Polysiphonia angustissima Kützing, 1864 accepted as Polysiphonia subtilissima Montagne, 1840
• Polysiphonia anisogona J.D.Hooker & Harvey, 1845
• Polysiphonia anomala Hollenberg, 1968
• Polysiphonia apiculata Hollenberg, 1968 accepted as Melanothamnus apiculatus (Hollenberg) Díaz- Tapia & Maggs, 2017
• Polysiphonia aquamara I.A.Abbott, 1947 accepted as Neosiphonia tongatensis (Harvey ex Kützing) M.-S.Kim & I.K.Lee, 1999 accepted as Melanothamnus tongatensis (Harvey ex Kützing) Díaz-Tapia & Maggs, 2017
• Polysiphonia arachnoidea (C.Agardh) Zanardini, 1840
• Polysiphonia arachnoidea var. purpurea C.Agardh, 1828 accepted as Polysiphonia purpurea (C.Agardh) J.Agardh, 1842 accepted as Polysiphonia sanguinea (C.Agardh) Zanardini, 1840
• Polysiphonia arborescens Kützing, 1843 accepted as Carradoriella elongata (Hudson) Savoie & G.W.Saunders, 2019
• Polysiphonia arctica J.Agardh, 1863
• Polysiphonia arenaria Harvey
• Polysiphonia arenaria Kützing
• Polysiphonia arenaria Postels & Ruprecht (uncertain)
• Polysiphonia arenicola Kützing
• Polysiphonia argentinica W.R.Taylor, 1939 accepted as Neosiphonia harveyi (Bailey) M.-S.Kim, H.-G.Choi, Guiry & G.W.Saunders, 2001 accepted as Melanothamnus harveyi (Bailey) Díaz-Tapia & Maggs, 2017
• Polysiphonia argus Kützing, 1864 accepted as Herposiphonia versicolor (Hooker & Harvey) Reinbold, 1899
• Polysiphonia armata J.Agardh, 1842 accepted as Polysiphonia subulifera (C.Agardh) Harvey, 1834 accepted as Vertebrata subulifera (C.Agardh) Kuntze, 1891
• Polysiphonia aspera Zanardini ex A.De Toni, 1907 (uncertain)
• Polysiphonia asperula (Kützing) Kützing
• Polysiphonia asperula Kützing
• Polysiphonia aterrima J.D.Hooker & Harvey, 1845 accepted as Vertebrata aterrima (J.Hooker & Harvey) Kuntze, 1891
• Polysiphonia atlantica Kapraun & J.N.Norris, 1982
• Polysiphonia atra Zanardini, 1847
• Polysiphonia atricapilla J.Agardh, 1863
• Polysiphonia atropurpurea Moore, 1837 accepted as Vertebrata fucoides (Hudson) Kuntze, 1891
• Polysiphonia atrorubens (Wahlenberg) Endlicher
• Polysiphonia atrorubescens (Dillwyn) Greville, 1824 accepted as Polysiphonia nigra (Hudson) Batters, 1902 accepted as Vertebrata nigra (Hudson) Díaz-Tapia & Maggs, 2017
• Polysiphonia attenuata Zanardini
• Polysiphonia attenuata Zanardini ex A.De Toni, 1907 (uncertain)
• Polysiphonia aurantiaca Kützing
• Polysiphonia aurata Harvey, 1855 accepted as Tiparraria aurata (Harvey) Womersley, 2003
• Polysiphonia australiensis Womersley, 1979
• Polysiphonia australis (C.Agardh) J.Agardh, 1863 accepted as Brongniartella australis (C.Agardh) F.Schmitz, 1893 accepted as Vertebrata australis (C.Agardh) Kuntze, 1891
• Polysiphonia awabiensis Noda
• Polysiphonia azorica O.C.Schmidt, 1929
• Polysiphonia badia (Dillwyn) Sprengel, 1827 accepted as Polysiphonia nigra (Hudson) Batters, 1902 accepted as Vertebrata nigra (Hudson) Díaz-Tapia & Maggs, 2017
• Polysiphonia badia Kützing, 1849 accepted as Neosiphonia sertularioides (Grateloup) K.W.Nam & P.J.Kang, 2012 accepted as Polysiphonia sertularioides (Grateloup) J.Agardh, 1863
• Polysiphonia badia var. funicularis (Meneghini) Kützing (uncertain)
• Polysiphonia baileyi (Harvey) J.Agardh
• Polysiphonia bajacali Hollenberg, 1961 accepted as Melanothamnus bajacali (Hollenberg) Díaz-Tapia & Maggs, 2017
• Polysiphonia balanicola Falkenberg, 1901 accepted as Polysiphonia funebris De Notaris ex J.Agardh, 1851
• Polysiphonia bambusina Meneghini
• Polysiphonia bangi Kützing, 1849 accepted as Brongniartella byssoides (Goodenough & Woodward) F.Schmitz, 1893 accepted as Vertebrata byssoides (Goodenough & Woodward) Kuntze, 1891
• Polysiphonia bangii (Kützing) Kützing, 1864 accepted as Brongniartella byssoides (Goodenough & Woodward) F.Schmitz, 1893 accepted as Vertebrata byssoides (Goodenough & Woodward) Kuntze, 1891
• Polysiphonia banyulensis Coppejans, 1976
• Polysiphonia barbatula Kützing, 1849
• Polysiphonia bartlingiana Kützing, 1843 accepted as Symphyocladiella bartlingiana (Kützing) D.Bustamante, B.Y.Won & T.O.Cho, 2019
• Polysiphonia baxteri A.H.S.Lucas, 1935
• Polysiphonia beaudettei Hollenberg, 1961
• Polysiphonia beguinotii Schiffner & Vatova, 1938
• Polysiphonia beguinottii Schiffner, 1938 accepted as Polysiphonia beguinotii Schiffner & Vatova, 1938
• Polysiphonia bellula De Notaris (uncertain)
• Polysiphonia beltoniorum Huisman, 2018
• Polysiphonia berkeleyi (Montagne) J.D.Hooker, 1847 accepted as Heterosiphonia berkeleyi Montagne, 1842
• Polysiphonia berkeleyi var. daviesii (J.D.Hooker & Harvey) J.D.Hooker, 1847 accepted as Heterosiphonia berkeleyi Montagne, 1842
• Polysiphonia berkeleyi var. davisii (Hooker f. & Harvey) Harvey
• Polysiphonia berkeleyi var. davisii (Hooker f. & Harvey) Hooker f. & Harvey
• Polysiphonia bharadwajae Sreenivasa Rao, 1967 accepted as Polysiphonia ferulacea Suhr ex J.Agardh, 1863 accepted as Melanothamnus ferulaceus (Suhr ex J.Agardh) Díaz-Tapia & Maggs, 2017
• Polysiphonia biasolettiana Zanardini
• Polysiphonia biasolettoana (C.Agardh) J.Agardh, 1842 accepted as Polysiphonia deusta (Roth) Sprengel, 1827
• Polysiphonia biasolettoana Zanardini, 1841 accepted as Polysiphonia deusta (Roth) Sprengel, 1827
• Polysiphonia bicornis Ohta, 1973
• Polysiphonia bicornis Sonder, 1880 (uncertain)
• Polysiphonia biformis Zanardini, 1860
• Polysiphonia bifurcata Hollenberg, 1945
• Polysiphonia binderi (J.Agardh) Goebel