• Melosira C.A. Agardh, 1824
• Melosira accinctus Hohn & Hellerman, 1963 (uncertain > unassessed)
• Melosira aculeifera Scheschukova-Poretzkaya in Scheschukova-Poretzkaya & Moissejeva, 1964 (uncertain > unassessed)
• Melosira adeliae Manguin, 1957 (uncertain > unassessed)
• Melosira aequalis Agardh, 1832 (uncertain > unassessed)
• Melosira africana Leuduger-Fortmorel, 1898 (uncertain > unassessed)
• Melosira agassizii Ostenfeld, 1909
• Melosira agassizii var. agassizii Ostenfeld, 1909 (uncertain > unassessed)
• Melosira agassizii var. malayensis Hustedt, 1942 (uncertain > unassessed)
• Melosira agria Pantocsek, 1905 (uncertain > unassessed)
• Melosira akkavaarensis Tynni, 1982 (uncertain > unassessed)
• Melosira albicans Sheshukova, 1961 (uncertain > unassessed)
• Melosira alphabetica Mann, 1937 (uncertain > unassessed)
• Melosira alternans Pouchet, 1893 (uncertain > unassessed)
• Melosira ambigua (Grunow) O.F.Müller (uncertain > unassessed)
• Melosira ambigua f. altaica Skabichevskij, 1966 (uncertain > unassessed)
• Melosira ambigua f. ambigua (Grunow in Van Heurck) Otto Müller, 1903 accepted as Melosira crenulata var. ambigua Grunow, 1882
• Melosira ambigua f. curvata A.P.Skabichevskij, 1960 (uncertain > unassessed)
• Melosira ambigua f. curvata Cheremisinova??, 1968 (uncertain > unassessed)
• Melosira ambigua f. spiralis Skuja, 1948 (uncertain > unassessed)
• Melosira ambigua f. spiroides N.A.Chalfina, 1966 (uncertain > unassessed)
• Melosira ambigua var. alpha Hustedt, 1927 (uncertain > unassessed)
• Melosira ambigua var. beta Hustedt, 1927 (uncertain > unassessed)
• Melosira ambigua var. desikacharya Rao & Awasthi, 1963 (uncertain > unassessed)
• Melosira ambigua var. krishna Rao & Awasthi, 1963 (uncertain > unassessed)
• Melosira ambigua var. laradura Rao & Awasthi, 1963 (uncertain > unassessed)
• Melosira ambigua var. puncticulosa (Otto Müller) (uncertain > unassessed)
• Melosira ambigua var. robusta Gasse, 1980 accepted as Aulacoseira gadebensis (Gasse, 1980) Mohan & Stone, 2016 †
• Melosira ambigua var. variata (Otto Müller) (uncertain > unassessed)
• Melosira americana Kützing, 1844 (uncertain > unassessed)
• Melosira americana f. americana Kützing, 1844 (uncertain > unassessed)
• Melosira americana f. nipponica Skvortzow, 1936 (uncertain > unassessed)
• Melosira anastomosans Grunow in Van Heurck, 1882 (uncertain > unassessed)
• Melosira angulata (Gregory) Rabenhorst, 1864 accepted as Orthosira angulata Gregory, 1857
• Melosira angulata var. angustissima Borutskii, 1952 (uncertain > unassessed)
• Melosira angustissima Neizvestnova-Zhadina, 1941 (uncertain > unassessed)
• Melosira annularis Eichwald, 1847 (uncertain > unassessed)
• Melosira anormal Van Heurck, 1882 (uncertain > unassessed)
• Melosira antarctica Van Heurck, 1909 (uncertain > unassessed)
• Melosira antiqua A.I.Moiseeva, 1963 † accepted as Alveolophora antiqua (A.I.Moisseeva) A.I.Moisseeva, 1990 †
• Melosira architecturalis Brun in Schmidt et al., 1892 † (uncertain > unassessed)
• Melosira arctica (Ehrenberg) Ralfs in Pritchard, 1861 accepted as Gaillonella arctica (Dickie) Ehrenberg, 1853 accepted as Melosira arctica var. arctica Dickie in litt., Ehrenberg, 1853
• Melosira arctica Dickie, 1852 (uncertain > unassessed)
• Melosira arctica var. arctica Dickie in litt., Ehrenberg, 1853 (uncertain > unassessed)
• Melosira arctica var. bornholmiensis Cleve-Euler, 1934 (uncertain > unassessed)
• Melosira arctica var. krembsii I. Kaczmarska & R. Jahn, 2006 (uncertain > unassessed)
• Melosira arctica var. subarctica (Otto Müller) (uncertain > unassessed)
• Melosira arcuata Pantocsek, 1892 (uncertain > unassessed)
• Melosira arenaria Moore ex Ralfs, 1843 accepted as Ellerbeckia arenaria (Moore ex Ralfs) R.M.Crawford, 1988 accepted as Melosira arenaria var. arenaria Moore ex Ralfs, 1843
• Melosira arenaria f. baikalensis Skvortzow, 1937 (uncertain > unassessed)
• Melosira arenaria f. ornata Skvortzow, 1937 (uncertain > unassessed)
• Melosira arenaria f. punctata Skvortzow, 1937 (uncertain > unassessed)
• Melosira arenaria f. teres (Brun) Tynni, 1982 accepted as Melosira teres Brun, 1892
• Melosira arenaria var. arenaria Moore ex Ralfs, 1843 (uncertain > unassessed)
• Melosira arenaria var. definita Østrup, 1908 (uncertain > unassessed)
• Melosira arenaria var. fossilis Pantocsek, 1913 (uncertain > unassessed)
• Melosira arenaria var. granulata Gutwinski, 1890 (uncertain > unassessed)
• Melosira arenaria var. hungarica Pantocsek, 1889 (uncertain > unassessed)
• Melosira arenaria var. laevis Héribaud, 1903 (uncertain > unassessed)
• Melosira arenaria var. nova Yakowleff, 1924 (uncertain > unassessed)
• Melosira arenaria var. ornata Pantocsek, 1913 (uncertain > unassessed)
• Melosira arenaria var. tertiaria Pantocsek, 1913 (uncertain > unassessed)
• Melosira arenaria var. varennarum (M. Peragallo & Heribaud in Heribaud) F.W. Mills, 1934 accepted as Melosira varennarum M. Peragallo & Héribaud in Héribaud, 1893
• Melosira arenaria var. vestita Pantocsek, 1913 (uncertain > unassessed)
• Melosira arenosa Moore ex Hassall, 1852 (uncertain > unassessed)
• Melosira arentii (Kolbe) Nagumo & Kobayasi, 1977 accepted as Cyclotella arentii Kolbe, 1948
• Melosira areolata A.I.Moissejeva, 1971 accepted as Alveolophora areolata A.I.Moiseeva, 1990 †
• Melosira areolata O.Müller, 1904 (uncertain > unassessed)
• Melosira argus Otto Müller, 1904 (uncertain > unassessed)
• Melosira argus f. alpha (uncertain > unassessed)
• Melosira argus f. alpha minor Otto Müller, 1904 (uncertain > unassessed)
• Melosira argus f. argus Otto Müller, 1904 (uncertain > unassessed)
• Melosira argus f. beta (uncertain > unassessed)
• Melosira argus f. beta minor Otto Müller, 1904 (uncertain > unassessed)
• Melosira argus var. granulosa (Otto Müller) (uncertain > unassessed)
• Melosira argus var. trimorpha Otto Müller (uncertain > unassessed)
• Melosira arundinacea F.S.Castracane degli Antelminelli (uncertain > unassessed)
• Melosira arundinacea f. arundinacea Castracane, 1894 (uncertain > unassessed)
• Melosira arundinacea f. minor Castracane in litt., 1893 (uncertain > unassessed)
• Melosira asiatica Brun in Schmidt et al., 1892 accepted as Cyclotella asiatica Brun in Brun & Tempère, 1889
• Melosira astridae D. Metzeltin & H. Lange-Bertalot, 2007 (uncertain > unassessed)
• Melosira atlymica Rubina, 1962 (uncertain > unassessed)
• Melosira aueri Cleve-Euler, 1948
• Melosira bacillosa Otto Müller, 1903 (uncertain > unassessed)
• Melosira bacillosa f. peregrina (Otto Müller) (uncertain > unassessed)
• Melosira bacillosa f. procera (Otto Müller) (uncertain > unassessed)
• Melosira bacillosa var. bacillosa (Otto Müller) (uncertain > unassessed)
• Melosira bacillosa var. minor (Otto Müller) (uncertain > unassessed)
• Melosira baicalensis (K.I.Meyer) Wislouch (uncertain > unassessed)
• Melosira baicalensis f. oblongopunctata Skvortzow & Meyer, 1928 (uncertain > unassessed)
• Melosira baicalensis f. soochowensis Skvortzov
• Melosira baicalensis f. tenuissima Skvortzov
• Melosira baicalensis var. baicalensis (Bethge) Hollerbakh & Krasavina, 1971 (uncertain > unassessed)
• Melosira baikalensis S.Wislouch, 1924
• Melosira baikalensis f. baikalensis (Meyer) Wislouch, 1924 accepted as Melosira islandica var. baicalensis Meyer, 1916
• Melosira baikalensis f. compacta Skvortzow, 1937 (uncertain > unassessed)
• Melosira baikalensis f. typica Skvortzow, 1937 (uncertain > unassessed)
• Melosira baileyi (H.L.Smith) Wolle, 1890 accepted as Cestodiscus baileyi H.L.Smith, 1878 †
• Melosira bellicosa Héribaud, 1903 (uncertain > unassessed)
• Melosira biharensis Pantocsek, 1886 (uncertain > unassessed)