Acanthoceras echionotum (J.Agardh) Kütz., 1849 accepted as Ceramium echionotum J.Agardh, 1844 (new combination reference)
Acanthoceras oxyacanthum Kützing, 1849 (original description)
Acanthoceras transcurrens Kützing, 1849 accepted as Ceramium echionotum J.Agardh, 1844 (original description)
Achnanthidium cryptocephalum Naegeli ex Kützing, 1849 (original description)
Achnanthidium flexellum f. flexellum (Kützing) Brébisson ex Kützing, 1849 accepted as Cymbella flexella Kützing, 1844 (new combination reference)
Acrocarpus gracilis Kützing, 1849 accepted as Ceratodictyon variabile (J.Agardh) R.E.Norris, 1987 (original description)
Amphipleura inflexa Brébisson ex Kützing, 1849 accepted as Climaconeis inflexa (Brébisson ex Kützing) E.J.Cox, 1982 (original description)
Amphiprora kuetzingii Brébisson ex Kützing, 1849 (original description)
Amphiprora latestriata Brébisson ex Kützing, 1849 (original description)
Amphiroa verruculosa Kützing, 1849 accepted as Amphiroa kuetzingiana Trevisan, 1845 (original description)
Amphora ostrearia var. ostrearia Brébisson ex Kützing, 1849 (original description)
Amphora quadrata Brébisson ex Kützing, 1849 (original description)
Batrachospermum suevorum Kützing, 1849 accepted as Batrachospermum keratophytum Bory, 1808 accepted as Paludicola keratophyta (Bory) M.L.Vis & Necchi, 2020 (original description)
Biddulphia elongata Meneghini in Kützing, 1849 (original description)
Botrydium pyriforme Kützing, 1849 (original description)
Ceratoneis gracilis Brébisson ex Kützing, 1849 (original description)
Ceratoneis longissima Brébisson, 1849 (original description)
Chaetomorpha aerea (Dillwyn) Kützing, 1849 (new combination reference)
Chaetophora flagellifera Kützing, 1849 (original description)
Chantransia alpina Kützing, 1849 accepted as Chantransia violacea var. alpina (Kützing) Rabenhorst, 1868 (original description)
Chantransia investiens Lenormand ex Kützing, 1849 accepted as Balbiania investiens (Lenormand ex Kützing) Sirodot, 1876 (original description)
Characium minutum A.Braun ex Kützing, 1849 accepted as Characiopsis minuta (A.Braun) Borzì, 1895 (original description)
Characium sieboldii A.Braun, 1849 accepted as Chlamydopodium sieboldii (A.Braun) Tsarenko, 2000 (original description)
Cocconeis britannica var. britannica Naegeli ex Kützing, 1849 (original description)
Cocconeis patavina Meneghini ms. in Kützing, 1849 (original description)
Cocconeis tenuissima Naegeli ex Kützing, 1849 (original description)
Cocconeis tenuissima var. cincta Kützing, 1849 (original description)
Cocconeis tenuissima var. laevis Kützing, 1849 (original description)
Cocconeis tenuissima var. striata Kützing, 1849 (original description)
Cocconema affine Kützing, 1849 (original description)
Cocconema bremii Naegeli ex Kützing, 1849 (original description)
Cocconema tumidum f. tumidum Brébisson ex Kützing, 1849 (original description)
Colletonema A. de Brébisson ex F.T. Kützing, 1849 (original description)
Colletonema americanum (Ehrenberg) Kützing, 1849 accepted as Naunema americanum Ehrenberg, 1845 (new combination reference)
Colletonema amphioxys (Ehrenberg) Kützing, 1849 accepted as Naunema amphioxys Ehrenberg, 1843 (new combination reference)
Colletonema eximium (Thwaites) Kützing, 1849 accepted as Schizonema eximium Thwaites, 1848 (new combination reference)
Colletonema lacustre (Agardh) Kützing, 1849 accepted as Schizonema lacustre C.Agardh, 1824 (new combination reference)
Colletonema viridulum Brébisson ex Kützing, 1849 (original description)
Conferva undulata Brébisson, 1849 accepted as Oedogonium undulatum A.Braun ex Hirn, 1900 (original description)
Corallina berteroi Montagne ex Kützing, 1849 (original description)
Corallina calliptera Kützing, 1849 accepted as Jania rosea (Lamarck) Decaisne, 1842 (original description)
Coscinodiscus auliscus Kützing, 1849 (original description)
Coscinodiscus concavus var. africanus Kützing, 1849 (original description)
Coscinodiscus craspedodiscus Kützing, 1849 (original description)
Coscinodiscus oceanicus (Ehrenberg) Kützing, 1849 accepted as Endictya oceanica Ehrenberg, 1845 (new combination reference)
Coscinodiscus pyxidicula Kützing, 1849 (original description)
Cyclotella actinocyclus (Ehrenberg) Kützing, 1849 accepted as Pyxidicula actinocyclus Ehrenberg, 1844 (new combination reference)
Cyclotella americana (Ehrenberg) Kützing, 1849 accepted as Discoplea americana Ehrenberg, 1844 (new combination reference)
Cyclotella astraea Kützing, 1849 accepted as Discoplea astraea Ehrenberg, 1844 † (new combination reference)
Cyclotella comta f. comta (Ehrenberg) Kützing, 1849 accepted as Lindavia comta (Ehrenberg) Nakov et al., 2015 (new combination reference)
Cyclotella coscinodiscus Kützing accepted as Discoplea coscinodiscus Ehrenberg, 1845 (new combination reference)
Cyclotella denticulata Kützing accepted as Discoplea denticulata Ehrenberg, 1844 (1845) (new combination reference)
Cyclotella dives (Ehrenberg) Kützing, 1849 accepted as Actinoptychus dives (Ehrenberg) Ehrenberg (new combination reference)
Cyclotella laevis (Ehrenberg) Kützing, 1849 accepted as Hyalodiscus laevis var. laevis Ehrenberg, 1845 (new combination reference)
Cyclotella mammilla Kützing accepted as Discoplea mammilla Ehrenberg, 1845 (new combination reference)
Cyclotella meneghiniana var. major Kützing, 1849 (original description)
Cyclotella operculata var. rectangula Kützing, 1849 (original description)
Cyclotella patagonica (Ehrenberg) Kützing, 1849 (new combination reference)
Cyclotella peruana Kützing accepted as Discoplea peruana Ehrenberg, 1842 (new combination reference)
Cyclotella physoplea Kützing accepted as Discoplea physoplea Ehrenberg, 1845 (new combination reference)
Cyclotella picta Kützing accepted as Discoplea picta Ehrenberg, 1845 (new combination reference)
Cyclotella rectangula Brébisson ex Rabenhorst, 1853 (original description)
Cyclotella rota (Ehrenberg) Kützing, 1849 accepted as Discoplea rota Ehrenberg, 1844 (new combination reference)
Cyclotella rotula Kützing, 1844 accepted as Discoplea rotula Ehrenberg, 1844 (new combination reference)
Cyclotella undata Kützing accepted as Discoplea undata Ehrenberg, 1844 (1845) (new combination reference)
Cymbella amphicephala Näegeli, 1849 (original description)
Cymbella delicatula Kützing, 1849 accepted as Delicatophycus delicatulus (Kützing) M.J.Wynne, 2019 (original description)
Cymbella laevis Nägeli, 1863 (original description)
Cymbella maxima Naegeli ex Kützing, 1849 (original description)
Denticula crassula Naegeli ex Kützing, 1849 (original description)
Denticula thermalis var. rupestris Kützing, 1849 (original description)
Diatoma gracillimum Naegeli in Kutzing, 1849 (original description)
Diatoma vulgare var. quadratum (Kützing) Kuetzing, 1849 accepted as Diatoma mesodon var. quadratum Kützing, 1844 (new combination reference)
Discoplea astraea Ehrenberg, 1844 † (original description)
Encyonema caespitosum Kützing, 1849 (original description)
Encyonema sigmoides (Ehrenberg) Kützing, 1849 (new combination reference)
Encyonema triangulum (Ehrenberg) Kützing, 1849 accepted as Gloeonema triangulum Ehrenberg, 1845 (new combination reference)
Enteromorpha acanthophora Kützing, 1849 accepted as Ulva acanthophora (Kützing) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003 (original description)
Enteromorpha aureola (C.Agardh) Kützing, 1849 accepted as Capsosiphon fulvescens (C.Agardh) Setchell & N.L.Gardner, 1920 (new combination reference)
Enteromorpha compressa var. novae-hollandiae Kützing, 1849 accepted as Enteromorpha bulbosa (Suhr) Montagne, 1846 accepted as Ulva hookeriana (Kützing) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003 (original description)
Enteromorpha corniculata Kützing, 1849 (original description)
Enteromorpha hookeriana Kützing, 1849 accepted as Ulva hookeriana (Kützing) H.S.Hayden, Blomster, Maggs, P.C.Silva, Stanhope & Waaland, 2003 (original description)
Enteromorpha minima Nägeli ex Kützing, 1849 accepted as Blidingia minima (Nägeli ex Kützing) Kylin, 1947 (original description)
Enteromorpha ramellosa Kützing, 1849 (original description)
Epithemia gregaria Brébisson in Kutzing, 1849 (original description)
Epithemia reticulata Naegeli ex Kützing, 1849 (original description)
Epithemia ventricosa var. gregaria (Brebisson ex Kutzing) Kützing, 1849 accepted as Epithemia gregaria Brébisson in Kutzing, 1849 (new combination reference)
Eunotia biceps Kützing, 1849 (original description)
Eunotia bigibba Kützing, 1849 (original description)
Eunotia flexuosa (Brébisson ex Kützing) Kützing, 1849 accepted as Synedra flexuosa var. flexuosa Brébisson ex Kützing, 1846 (new combination reference)
Eunotia pachycephala Kützing, 1849 (original description)
Eupodiscus crux (Ehrenberg) Kützing, 1849 (new combination reference)
Eupodiscus petersii (Ehrenberg) Kützing, 1849 (new combination reference)
Euptilota pappeana Kützing, 1849 accepted as Heteroptilon pappeanum (Kützing) Hommersand, 2006 (original description)
Exilaria flexa Brebisson in Kutzing, 1849 (original description)
Fragilaria pusilla Kützing, 1849 (original description)
Frustulia orsiniana Meneghini ex Kutzing, 1849 (original description)
Ginnania irregularis Kützing, 1849 accepted as Nemastoma dichotomum J.Agardh, 1842 (original description)
Gomphonema auritum A.Braun ex Kützing, 1849 (original description)
Gomphonema auritum f. auritum Braun in litt., Kutzing, 1849 (original description)