DiatomBase
Between brackets is the number of accepted extant species
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- Bacillariophyceae (5 957)
- Subclass Bacillariophyceae incertae sedis (189)
- Subclass Bacillariophycidae (4 408)
- Superorder Bacillariophycanae (4 083)
- Order Achnanthales (438)
- Order Bacillariales (357)
- Family Bacillariaceae Ehrenberg, 1831 (352)
- Genus Allonitzschia A. Mann, 1925
- Genus Alveus I. Kaczmarska & G.A. Fryxell, 1996
- Genus Bacillaria J.F. Gmelin, 1788 (3)
- Genus Cylindrotheca L. Rabenhorst, 1859 (2)
- Genus Cymatonitzschia R. Simonsen, 1974
- Genus Cymbellonitzschia F. Hustedt in A. Schmidt et al., 1924 (1)
- Genus Denticula F.T. Kützing, 1844 (6)
- Genus Denticulopsis R. Simonsen, 1979 (1)
- Genus Fragilariopsis F. Hustedt in A. Schmidt et al., 1913 (6)
- Genus Gomphonitzschia A. Grunow, 1868 (1)
- Genus Gomphotheca N.I. Hendey & P.A. Sims, 1982
- Genus Hantzschia A. Grunow, 1877 (28)
- Genus Neodenticula Akiba & Yanagisawa, 1986 †
- Genus Nitschia
- Genus Nitzschia A.H. Hassall, 1845 (241)
- Species Nitzschia abbreviata Hustedt in Schmidt et al., 1924
- Species Nitzschia abelmanniae A.Witkowski & Lange-Bertalot in Witkowski et al., 2015
- Species Nitzschia abendens Grunow
- Species Nitzschia abludens Grunow, 1878
- Species Nitzschia abonuensis Foged, 1966
- Species Nitzschia abraensis Foged, 1966
- Species Nitzschia abridia Camburn in Camburn, Lowe & Stoneburner, 1978
- Species Nitzschia accedens Hustedt
- Species Nitzschia accommodata Hustedt, 1949
- Species Nitzschia aciculariformis Manguin, 1957
- Species Nitzschia acicularioides Hustedt, 1959
- Species Nitzschia acicularioides Archibald, 1966
- Species Nitzschia acicularis (Kützing) W.Smith, 1853
- Species Nitzschia acicularis Frenguelli, 1923
- Species Nitzschia acidoclinata Lange-Bertalot, 1976
- Species Nitzschia aclita Cleve, 1879
- Species Nitzschia actinastroides (Lemmermann) van Goor, 1925 accepted as Synedra actinastroides var. actinastroides Lemmermann, 1900
- Species Nitzschia actydrophila Hasle, 1965
- Species Nitzschia acula (Kützing) Hantzsch, 1861 accepted as Synedra acula Kützing, 1844
- Species Nitzschia acuminata (W.Smith) Grunow, 1880 accepted as Tryblionella acuminata W.Smith, 1853
- Species Nitzschia acus
- Species Nitzschia acuta Cleve, 1878
- Species Nitzschia acuta Peragallo & Peragallo, 1899
- Species Nitzschia acutissima Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia acutiuscula
- Species Nitzschia adakensis Hein, 1990
- Species Nitzschia adamata Hustedt, 1957
- Species Nitzschia adamatoides K. Krammer & H. Lange-Bertalot, 1997
- Species Nitzschia adapta Hustedt, 1949
- Species Nitzschia adducta Hustedt, 1955
- Species Nitzschia adductoides Archibald, 1982
- Species Nitzschia adeliae Frenguelli, 1960
- Species Nitzschia adeliana Manguin, 1960
- Species Nitzschia adiembraensis Foged, 1966
- Species Nitzschia admissa Hustedt, 1957
- Species Nitzschia admissoides Cholnoky, 1968
- Species Nitzschia adriatica
- Species Nitzschia aequalis Hustedt, 1949
- Species Nitzschia aequatorialis Heiden, 1928
- Species Nitzschia aequorea Hustedt, 1939
- Species Nitzschia aerophila Hustedt, 1942
- Species Nitzschia aerophiloides H.P. Gandhi, 1998 accepted as Nitzschia aerophiloides H.P.Gandhi ex Karthick, 2020
- Species Nitzschia aerophiloides H.P.Gandhi ex Karthick, 2020
- Species Nitzschia aestatis Giffen, 1973
- Species Nitzschia aestuarii
- Species Nitzschia affinis Manguin in Bourrelly & Manguin, 1952
- Species Nitzschia africana Grunow in Cleve & Möller, 1879
- Species Nitzschia africana Leuduger-Fortmorel, 1898
- Species Nitzschia agapica Skabichevskaya, 1984
- Species Nitzschia agnewii Cholnoky, 1962
- Species Nitzschia agnita Hustedt, 1957
- Species Nitzschia aketechiensis Foged, 1966
- Species Nitzschia alandica Tynni, 1980
- Species Nitzschia alaskana Patrick & Freese, 1961
- Species Nitzschia alata Leuduger-Fortmorel, 1892
- Species Nitzschia alba J.C.Lewin & R.A.Lewin, 1967
- Species Nitzschia albicostalis B.E.Volcani & C.-W.Li
- Species Nitzschia alcyoneae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia alexandrina (Cholnoky) Lange-Bertalot & Simonsen, 1978 accepted as Nitzschia elliptica var. alexandrina Cholnoky, 1958
- Species Nitzschia alicae Hlúbiková & Ector, 2009
- Species Nitzschia allansonii Cholnoky, 1958
- Species Nitzschia alpha Heinzerling, 1908
- Species Nitzschia alpina Hustedt, 1943
- Species Nitzschia alpinobacillum Lange-Bertalot, 1993
- Species Nitzschia amabilis Suzuki, 2010
- Species Nitzschia ambigua Manguin, 1964
- Species Nitzschia americana Hasle, 1964
- Species Nitzschia americana Bennett & Kociolek in Kociolek et al., 2014
- Species Nitzschia amisaensis Foged, 1966
- Species Nitzschia amoena Hustedt in Schmidt et al., 1924
- Species Nitzschia amoyensis Skvortzow, 1929
- Species Nitzschia amphibia Grunow, 1862
- Species Nitzschia amphibioides Hustedt, 1942
- Species Nitzschia amphicephala Grunow in Cleve & Grunow, 1880
- Species Nitzschia amphilepta (Ehrenberg) Ralfs, 1861 accepted as Eunotia amphilepta Ehrenberg, 1845
- Species Nitzschia amphioxoides Hustedt, 1959
- Species Nitzschia amphioxys (Ehrenberg) W.Smith, 1853 accepted as Hantzschia amphioxys (Ehrenberg) Grunow, 1880
- Species Nitzschia amphiplectans Hustedt accepted as Nitzschia amplectens Hustedt, 1957
- Species Nitzschia amphiprora Grunow in Cleve & Grunow, 1880
- Species Nitzschia amphiuris Roll, 1937
- Species Nitzschia amphoroides (Grunow in Cleve & Grunow) Cleve, 1882 accepted as Hantzschia amphoroides Grunow in Cleve & Grunow, 1880
- Species Nitzschia amplectens Hustedt, 1957
- Species Nitzschia amundoni Aleem, 1973
- Species Nitzschia anassae Cholnoky, 1957
- Species Nitzschia anderabensis Foged, 1959
- Species Nitzschia andesitica Pantocsek, 1889
- Species Nitzschia andicola H. Lange-Bertalot & Rumrich in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia anguillula Schumann, 1867
- Species Nitzschia angularis W.Smith, 1853
- Species Nitzschia angulata Hasle, 1972
- Species Nitzschia angusta
- Species Nitzschia angustata (W.Smith) Grunow, 1880 accepted as Tryblionella angustata var. angustata W. Smith, 1853
- Species Nitzschia angustata sensu Fontell, 1917
- Species Nitzschia angustatula Lange-Bertalot, 1987
- Species Nitzschia angustecarinata Hustedt, 1956
- Species Nitzschia angusteforaminata Lange-Bertalot, 1980
- Species Nitzschia angustiprotracta Mikhailov, 1984
- Species Nitzschia angustissima Hustedt in Schmidt et al., 1924
- Species Nitzschia aniae Lange-Bertalot, 1993
- Species Nitzschia ankobraensis Foged, 1966
- Species Nitzschia annewillemsiana Hamsher et al., 2016
- Species Nitzschia anomala Proschkina-Lavrenko, 1963
- Species Nitzschia antarctica Okuno, 1954
- Species Nitzschia antediluviana
- Species Nitzschia antillarum (Cleve & Grunow in Cleve) Meister, 1937 accepted as Denticula antillarum Cleve, 1878
- Species Nitzschia antiqua Pantocsek, 1886
- Species Nitzschia apiceconica Kufferath, 1956
- Species Nitzschia apiculata (Gregory) Grunow, 1878 accepted as Tryblionella apiculata Gregory, 1857
- Species Nitzschia apiculata (W.Gregory) Grunow, 1880 accepted as
- Species Nitzschia apowaensis Foged, 1966
- Species Nitzschia apropongensis Foged, 1966
- Species Nitzschia aquaea
- Species Nitzschia araucana Vouilloud & Kociolek in Kociolek & Vouilloud, 2020
- Species Nitzschia archibaldii Lange-Bertalot, 1980
- Species Nitzschia arctica
- Species Nitzschia arcuata Gregory in Greville, 1859
- Species Nitzschia arcuatosigmoidea
- Species Nitzschia arcula Gersonde, 1991
- Species Nitzschia arculus Suringar, 1867 (1868)
- Species Nitzschia arculus Suringar, 1867
- Species Nitzschia arcus Bulnheim, 1859
- Species Nitzschia ardua Cholnoky, 1961
- Species Nitzschia aremonica Archibald, 1983
- Species Nitzschia arenaria Brebisson ex W. Smith Collection
- Species Nitzschia arenosa M.Garcia-Baptista, 1992
- Species Nitzschia areolata Hustedt, 1952
- Species Nitzschia arierae Bing Liu, S.Blanco & B.Q.Huang, 2015
- Species Nitzschia armoricana (Kützing) Grunow, 1862 accepted as Synedra armoricana Kützing, 1844
- Species Nitzschia armoricana Peragallo & Peragallo, 1900
- Species Nitzschia articuliformis Skvortzov, 1975
- Species Nitzschia asiatica Tempère & Brun in Brun & Tempère, 1889
- Species Nitzschia asperula T.Marsson, 1900
- Species Nitzschia asterionelloides Otto Müller, 1905
- Species Nitzschia asteropeae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia astridi Aleem, 1973
- Species Nitzschia asymbasia Hohn, 1961
- Species Nitzschia atlantica (Cleve) F.W. Mills, 1934 accepted as Nitzschia pungens var. atlantica Cleve, 1897
- Species Nitzschia atlantica (Paasche) Hasle, 1972 accepted as Fragilariopsis atlantica Paasche, 1961
- Species Nitzschia atlantica (Cleve) Cleve, 1901 accepted as Nitzschia pungens var. atlantica Cleve, 1897
- Species Nitzschia atomus Hustedt, 1950
- Species Nitzschia attenuata Mikhailov, 1984
- Species Nitzschia attenuata Østrup, 1913
- Species Nitzschia aurantiaca Schoeman, 1973
- Species Nitzschia aurariae Cholnoky, 1965
- Species Nitzschia aurica Gersonde, 1991
- Species Nitzschia auricula R. Gersonde in Harwood & Maruyama, 1992
- Species Nitzschia australis (Peragallo) A.Mann, 1937 accepted as Nitzschia dubia var. australis Peragallo, 1921
- Species Nitzschia australocommutata Hamsher et al., 2016
- Species Nitzschia australodesertorum Lehmkuhl, T. Ludwig & C. Bicudo, 2019
- Species Nitzschia austriaca Hustedt, 1959
- Species Nitzschia bacata Hustedt, 1937
- Species Nitzschia bacillariaeformis Hustedt, 1922
- Species Nitzschia bacilliformis Hustedt, 1922
- Species Nitzschia bacillum Hustedt, 1922
- Species Nitzschia baculum Frenguelli, 1949 †
- Species Nitzschia baculum Frenguelli & Orlando, 1959
- Species Nitzschia baculumata Kufferath, 1956
- Species Nitzschia baicalamphibia Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baicalangustata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baicalangustior Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baicalomedia Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baicalorecta Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baicalsublinearis Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baicaltrivialis Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia baikalensis Skvortzow, 1937
- Species Nitzschia balatonis Grunow, 1880
- Species Nitzschia balcanica Hustedt, 1945
- Species Nitzschia baltica (Juhlin-Dannfelt) M. Peragallo, 1903 accepted as Homoeocladia baltica Juhlin-Dannfelt, 1882
- Species Nitzschia bansoensis Foged, 1966
- Species Nitzschia barbieri M. Peragallo, 1921 accepted as Fragilariopsis barbieri (M. Peragallo) Cefarelli, Ferrario & Lundholm, 2021
- Species Nitzschia barca Hohn & Hellerman, 1966
- Species Nitzschia barkleyi Hustedt, 1952
- Species Nitzschia barronii Gersonde, 1991
- Species Nitzschia barrowiana Patrick & Freese, 1961
- Species Nitzschia bartholomei Grunow accepted as Nitzschia lorenziana var. bartholomei Grunow in Cleve & Grunow, 1880
- Species Nitzschia bathurstensis M.H.Giffen, 1970
- Species Nitzschia bavarica Hustedt, 1953
- Species Nitzschia beagleana Patrick, 1970
- Species Nitzschia behrei Hustedt, 1959
- Species Nitzschia bella Sovereign, 1963
- Species Nitzschia bergii A.Cleve, 1953
- Species Nitzschia beyeri Lange-Bertalot, 2004
- Species Nitzschia biacrula Hohn & Hellermann, 1963
- Species Nitzschia biakensis Cholnoky, 1963
- Species Nitzschia bicapitata Cleve, 1901
- Species Nitzschia biceps (Schumann) M. Peragallo, 1903 accepted as Homoeocladia biceps Schumann, 1867
- Species Nitzschia biconicacuta Kufferath, 1957
- Species Nitzschia bicostata Hyyppa, 1932
- Species Nitzschia bicrena Hohn & Hellerman, 1963
- Species Nitzschia bicuneata Grunow, 1880
- Species Nitzschia bicuspidata Pantocsek, 1889
- Species Nitzschia bifurcata Kaczmarska & Licea, 1986
- Species Nitzschia bilineata Grunow in Cleve & Möller, 1878
- Species Nitzschia biloba Meyer, 1938
- Species Nitzschia bilobata W.Smith, 1853
- Species Nitzschia biplacata
- Species Nitzschia birostrata W.Smith, 1853
- Species Nitzschia bisculpta A.Mann, 1925
- Species Nitzschia bita Hohn & Hellermann, 1963
- Species Nitzschia bituminosa
- Species Nitzschia biundulata Al-Handal, J.Zimm., R.Jahn, Torstensson, A. & Wulff, A., 2019
- Species Nitzschia bizertensis B.Smida, N.Lundholm, A.S.Hlaili & H.H.Mabrouk, 2014
- Species Nitzschia blankaartensis Denys & Lange-Bert., 1998
- Species Nitzschia bleischii Janisch in Rabenhorst, 1864
- Species Nitzschia bleischii Janisch in Bleisch, 1863
- Species Nitzschia boettcheriana
- Species Nitzschia boliviana E.A.Morales & M.L.Vis, 2007
- Species Nitzschia bombiformis Grunow accepted as Nitzschia constricta var. bombiformis Grunow, 1880
- Species Nitzschia borealis (Grunow) Thum accepted as Nitzschia brebissoni var. borealis Grunow in Cleve & Möller, 1882
- Species Nitzschia borgei Skvortzow, 1971
- Species Nitzschia bosumtwiensis Foged, 1966
- Species Nitzschia braarudii G.R.Hasle, 1960
- Species Nitzschia brachygramma D.G.Mann & Trobajo, 2014
- Species Nitzschia brebissoni
- Species Nitzschia brebissonii W.Smith, 1853
- Species Nitzschia bremensis Hustedt, 1930
- Species Nitzschia brevior (Manguin ex Kociolek & Reviers) Gerd Moser accepted as Nitzschia luzonensis f. brevior Manguin ex Kociolek & Reviers, 1996
- Species Nitzschia brevirostris Hustedt, 1955
- Species Nitzschia brevissima Grunow, 1880 accepted as Nitzschia obtusa var. brevissima Van Heurck, 1885
- Species Nitzschia brevistriata Grunow in Cleve & Grunow, 1880
- Species Nitzschia brightwellii Kitton, 1861
- Species Nitzschia brittonii Hagelstein, 1939
- Species Nitzschia brunoi Lange-Bertalot in Lange-Bertalot & Metzeltin, 1996
- Species Nitzschia bryophila (Hustedt) Hustedt, 1943 accepted as Nitzschia frustulum var. bryophila Hustedt, 1937
- Species Nitzschia bryophila Petersen
- Species Nitzschia buceros Cholnoky, 1968
- Species Nitzschia bukensis H. Peragallo in Peragallo & Peragallo, 1911
- Species Nitzschia bulnheimiana (Rabenhorst) H.L. Smith, 1874-1879 accepted as Homoeocladia bulnheimiana Rabenhorst, 1862
- Species Nitzschia burcklia Schrader, 1974
- Species Nitzschia buschbeckii Witkowski, Lange-Bertalot & Ruppel, 2004
- Species Nitzschia cacumina Giffen, 1973
- Species Nitzschia calamae Frenguelli, 1936
- Species Nitzschia calcicola Aleem & Hustedt, 1951
- Species Nitzschia calcuttensis (Skvortzov, 2012)
- Species Nitzschia caledonensis Schoeman, 1973
- Species Nitzschia calica
- Species Nitzschia californica Schrader, 1973
- Species Nitzschia calva Andrews, 1970
- Species Nitzschia campechiana Grunow, 1880
- Species Nitzschia caparti Kufferath, 1948
- Species Nitzschia capensis Cholnoky, 1959
- Species Nitzschia capitallata
- Species Nitzschia capitata Østrup, 1913 accepted as Homoeocladia capitata H.L. Smith, 1874
- Species Nitzschia capitata Heiden, 1928
- Species Nitzschia capitata Fritsch & Rich, 1929
- Species Nitzschia capitellata Hustedt, 1922
- Species Nitzschia capitellata sensu Cleve-Euler, 1934
- Species Nitzschia capitularis Cholnoky, 1961
- Species Nitzschia capuluspalae Simonsen, 1965
- Species Nitzschia carahii Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia carinaacuta Mikhailov, 1985
- Species Nitzschia carinospeciosa Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia carnicobarica Desikachary & Prema, 1987
- Species Nitzschia carnico-barica
- Species Nitzschia castracanei Hasle, 1974
- Species Nitzschia celaenoae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia centralis Khabakov, 1945
- Species Nitzschia chabaudii Manguin, 1954
- Species Nitzschia challengeri Schrader, 1973
- Species Nitzschia chalonii Van Heurck
- Variety Nitzschia chalonii var. chalonii Van Heurck, 1909
- Variety Nitzschia chalonii var. delicatissima Van Heurck, 1909
- Variety Nitzschia chalonii var. tenuistriata Van Heurck, 1909
- Species Nitzschia chandolensis H.P. Gandhi, 1998 accepted as Nitzschia chandolensis H.P.Gandhi ex Karthick, 2020
- Species Nitzschia chandolensis H.P.Gandhi ex Karthick, 2020
- Species Nitzschia chardezii Van de Vijver & Beyens, 2002
- Species Nitzschia chasei Choln., 1954
- Species Nitzschia chasmaensis Foged, 1959
- Species Nitzschia chauhanii H.P.Gandhi, 1998 accepted as Nitzschia chauhanii H.P.Gandhi ex Karthick, 2020
- Species Nitzschia chauhanii H.P.Gandhi ex Karthick, 2020
- Species Nitzschia chilensis Hustedt, 1927
- Species Nitzschia chinensis Skvortzow, 1932
- Species Nitzschia chuchiligaensis Foged, 1966
- Species Nitzschia chungara Rumrich & H. Lange-Bertalot in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia chuniana Manguin, 1964
- Species Nitzschia chutteri Archibald, 1966
- Species Nitzschia circumsuta (Bailey) Grunow, 1880 accepted as Tryblionella circumsuta (Bailey) Ralfs, 1861
- Species Nitzschia citrus Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia claasseniae Cholnoky, 1958
- Species Nitzschia clandestina Manguin, 1964
- Species Nitzschia clarissima H.Peragallo & M.Peragallo, 1899
- Species Nitzschia clausii Hantzsch, 1860
- Species Nitzschia clausiiformis Gandhi, 1961
- Species Nitzschia claviceps Schrader, 1976
- Species Nitzschia clavofixa König, 1959
- Species Nitzschia clementei Gombos A. M. Jr., 1976
- Species Nitzschia clementia Gombos, 1976
- Species Nitzschia clevei (Grunow in Cleve & Grunow) Peragallo & Peragallo, 1900 accepted as Gomphonitzschia clevei Grunow, 1880
- Species Nitzschia closterium (Ehrenberg) W.Smith, 1853
- Species Nitzschia closterium Eulenstein, 1868
- Species Nitzschia closteroides Hasle, 1956
- Species Nitzschia coarctata Grunow, 1880
- Species Nitzschia cocconeiformis Grunow, 1880
- Species Nitzschia columbiana Sovereign, 1958
- Species Nitzschia communata Grunow, 1880
- Species Nitzschia communis Rabenhorst, 1860
- Species Nitzschia commutata Grunow, 1880
- Species Nitzschia commutatoides Lange-Bertalot, 1987
- Species Nitzschia compacta Hustedt, 1958
- Species Nitzschia compactifibulata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia composita Giffen, 1971
- Species Nitzschia compressa (Bailey) C.S.Boyer, 1916 accepted as Tryblionella compressa (J.W.Bailey) M.Poulin, 1990
- Species Nitzschia concinna Grunow, 1880-1885
- Species Nitzschia concordia Fryxell & Kaczmarska, 1994
- Species Nitzschia condemnata Cholnoky, 1968
- Species Nitzschia conferta (Richter) M. Peragallo, 1903 accepted as Homoeocladia conferta Richter, 1879
- Species Nitzschia confinis Hustedt, 1949
- Species Nitzschia conformata Hustedt, 1952
- Species Nitzschia confusa Hustedt accepted as Nitzschia confinis Hustedt, 1949
- Species Nitzschia congolensis Hustedt, 1949
- Species Nitzschia consimilis (Grunow) M. Peragallo, 1903 accepted as Nitzschia sigma var. consimilis Grunow, 1878
- Species Nitzschia constricta (Gregory) Grunow, 1880 accepted as Psammodictyon constrictum f. parvum (Grunow) Belegratis, Louvrou & Economou-Amilli, 2012
- Species Nitzschia consummata Hustedt, 1949
- Species Nitzschia contorta Mereschkowsky, 1901
- Species Nitzschia copiastriata Hohn & Hellerman, 1966
- Species Nitzschia corpulenta Hendey, 1958
- Species Nitzschia costata Meister, 1937
- Species Nitzschia costata Pantocsek, 1892
- Species Nitzschia costei L.Tudesque, F.Rimet & L.Ector, 2008
- Species Nitzschia coudertii Héribaud in Héribaud et al., 1920
- Species Nitzschia coutei Maillard, 1978
- Species Nitzschia crassa (Pantocsek) F.W. Mills, 1934 accepted as Hantzschia crassa var. crassa Pantocsek, 1902
- Species Nitzschia crassepunctata Archibald, 1966
- Species Nitzschia creticola Østrup, 1910
- Species Nitzschia cryptocephala Roll, 1937
- Species Nitzschia cryptostriata Hohn & Hellerman, 1966
- Species Nitzschia csaszkaae (Pantocsek)
- Species Nitzschia cuba
- Species Nitzschia cucumis Konig, 1959
- Species Nitzschia cuneata Suringar, 1870
- Species Nitzschia cuneata Suringar, 1867
- Species Nitzschia curiosa Proschkina-Lavrenko, 1963
- Species Nitzschia cursoria (Donkin) Grunow in Cleve & Grunow, 1880 accepted as Bacillaria cursoria Donkin, 1858
- Species Nitzschia curta (Van Heurck) Hasle, 1972 accepted as Fragilaria curta Van Heurck, 1909
- Species Nitzschia curvata Compère, 1981
- Species Nitzschia curvatula Marchesoni, 1946
- Species Nitzschia curvilineata Hustedt, 1922
- Species Nitzschia curvipunctata Cholnoky, 1963
- Species Nitzschia curvirectangularis Kufferath, 1956
- Species Nitzschia curvirostris Cleve
- Species Nitzschia curvula W.Smith, 1856 accepted as Stenopterobia curvula (W.Smith) Krammer, 1987
- Species Nitzschia curvula (Kützing) Ralfs in Pritchard, 1861 accepted as Synedra curvula Kützing, 1844
- Species Nitzschia curvulum Gaud, 1974
- Species Nitzschia cuspidata Hasle, 1965
- Species Nitzschia custodis Cholnoky, 1960
- Species Nitzschia cylindrica Burckle, 1972
- Species Nitzschia cylindriformis Hasle, 1984 accepted as Fragilariopsis cylindriformis (Hasle) Hasle, 1993
- Species Nitzschia cylindroformis Hasle in Hasle & Booth, 1984
- Species Nitzschia cylindrus (Grunow) Hasle, 1972
- Species Nitzschia dadwinensis Foged, 1966
- Species Nitzschia dagmannii Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia dakariense Guermeur, 1954
- Species Nitzschia dakariensis Guermeur, 1954
- Species Nitzschia damasi Hustedt, 1949
- Species Nitzschia davidsonii Grunow & Dickie, 1880
- Species Nitzschia dealpina Lange-Bertalot & Hofmann in Lange-Bertalot, 1993
- Species Nitzschia debilis (Arnott) Grunow, 1880 accepted as Tryblionella debilis Arnott ex O'Meara, 1873
- Species Nitzschia debilis Pantocsek, 1902
- Species Nitzschia decipiens Hustedt, 1958
- Species Nitzschia decora Kitton, 1873
- Species Nitzschia definita Grove & Sturt, 1887
- Species Nitzschia delauneyi Manguin in Bourrelly & Manguin, 1952
- Species Nitzschia delicatisima H. Kobayasi in Kobayasi et al., 1977
- Species Nitzschia delicatissima Cleve, 1897
- Species Nitzschia delicatula Hasle, 1965
- Species Nitzschia delicatula Skvortzow, 1946
- Species Nitzschia delognei Grunow, 1880
- Species Nitzschia demota Archibald, 1971
- Species Nitzschia densuensis Foged, 1966
- Species Nitzschia dentatum Suriyanti & Usup, 2017
- Species Nitzschia denticula Grunow, 1880 accepted as Denticula kuetzingii Grunow, 1862
- Species Nitzschia denticulata Skvortzow, 1935
- Species Nitzschia denticulata Hirn, 1900
- Species Nitzschia denticuloides Hustedt, 1942
- Species Nitzschia denticuloides Schrader, 1976
- Species Nitzschia desertorum Hustedt, 1949
- Species Nitzschia destituta Bennett & Kociolek in Kociolek et al., 2014
- Species Nitzschia dianae (Ehrenberg) Ralfs in Pritchard, 1861 accepted as Eunotia dianae Ehrenberg, 1840
- Species Nitzschia diaphana Cleve, 1896
- Species Nitzschia dicrogramma D.G.Mann & Trobajo, 2014
- Species Nitzschia diducta Hustedt, 1938
- Species Nitzschia didyma Hustedt, 1952
- Species Nitzschia didyma Liu & Chin, 1980
- Species Nitzschia dietrichii Simonsen, 1974
- Species Nitzschia dilatata H. Peragallo in Tempère & Peragallo, 1889-1895
- Species Nitzschia diluta Archibald, 1966
- Species Nitzschia diluvialis Cleve, 1883
- Species Nitzschia diluviana Cleve in Cleve & Jentzsch, 1882
- Species Nitzschia dippelii Grunow, 1882
- Species Nitzschia directa Pantocsek, 1902
- Species Nitzschia diserta Hustedt, 1949
- Species Nitzschia disputata J.R.Carter, 1971
- Species Nitzschia dissipata (Kützing) Rabenhorst, 1860 accepted as Synedra dissipata var. dissipata Kützing, 1844
- Species Nitzschia dissipata Lange-Bertalot in Lange-Bertalot & Metzeltin, 1996
- Species Nitzschia dissipatoides Archibald, 1982
- Species Nitzschia distans W.Gregory, 1857
- Species Nitzschia distans sensu Brockmann, 1950
- Species Nitzschia distantoides Hustedt, 1958
- Species Nitzschia divaricata Meunier, 1910
- Species Nitzschia divergens Hustedt, 1952
- Species Nitzschia diversa Hustedt, 1959
- Species Nitzschia diversecostata Brun, 1894
- Species Nitzschia dobosziana Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia doljensis Pantocsek, 1886
- Species Nitzschia donahuei Desikachary & Gowthaman in Desikachary, Gowthaman & Latha, 1987
- Species Nitzschia donahuensis Schrader, 1976
- Species Nitzschia draveillensis Coste & Ricard, 1980
- Species Nitzschia droebakensis Hasle, 1964
- Species Nitzschia dubia W.Smith, 1853
- Species Nitzschia dubiformis Hustedt, 1939
- Species Nitzschia dubiiformis Hustedt, 1939
- Species Nitzschia dubioides Hustedt, 1955
- Species Nitzschia dubravicensis (Grunow) F.W. Mills, 1934 accepted as Hantzschia dubravicensis Grunow, 1882
- Species Nitzschia dura Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia ebroicensis Maillard, 1971
- Species Nitzschia eburnea Zanon, 1941
- Species Nitzschia efferans Schrader, 1976
- Species Nitzschia eglei Lange-Bertalot, 1987
- Species Nitzschia ehrenbergii Ralfs in Pritchard, 1861
- Species Nitzschia ehrenbergii Schumann, 1862
- Species Nitzschia electrae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia elegans Hustedt, 1956
- Species Nitzschia elegantula Grunow, 1881
- Species Nitzschia elliptica Hustedt
- Species Nitzschia elongata Hantzsch, 1860 accepted as Nitzschia vivax var. elongata Hantzsch, 1860
- Species Nitzschia elongata Hassal, 1845 accepted as Nitzschia sigmoidea (Nitzsch) W.Smith, 1853
- Species Nitzschia entomon (Ehrenberg) Ralfs in Pritchard, 1861 accepted as Synedra entomon Ehrenberg, 1841
- Species Nitzschia epiphytica O.Müller, 1905
- Species Nitzschia epiphyticoides Hustedt, 1949
- Species Nitzschia epithemiformis Lange-Bertalot, 1980
- Species Nitzschia epithemoides Grunow, 1880
- Species Nitzschia eppressa Carter, 1966
- Species Nitzschia epsilon Kitton ex De Toni, 1892
- Species Nitzschia erlandssonii Cholnoky, 1954
- Species Nitzschia erosa Giffen, 1967
- Species Nitzschia etchegoinia Hanna & Grant, 1929
- Species Nitzschia etoshensis Cholnoky, 1966
- Species Nitzschia eutinensis H.Lange-Bertalot & M.Werum, 2014
- Species Nitzschia evenescens Schrader, 1976
- Species Nitzschia examinanda Cholnoky, 1960
- Species Nitzschia exilis Sovereign, 1958
- Species Nitzschia exilis Archibald, 1966
- Species Nitzschia eximia Grunow in Cleve & Grunow, 1880
- Species Nitzschia extincta Kozyrenko & Sheshukova-Poretskaya, 1967
- Species Nitzschia faba Frenguelli, 1926
- Species Nitzschia fabiennejansseniana Cocquyt & Ryken, 2017
- Species Nitzschia falcata Otto Müller, 1905
- Species Nitzschia famelica (Kützing) Rabenhorst, 1863 accepted as Synedra famelica var. famelica Kützing, 1844
- Species Nitzschia fasciculata (Grunow) Grunow, 1881
- Species Nitzschia febigeri Grunow, 1880
- Species Nitzschia febigerii Grunow in Cleve & Grunow, 1880
- Species Nitzschia fenestralis D. Grady, D.G. Mann & Trobajo, 2020
- Species Nitzschia fenestralis D. Grady, D.G. Mann & Trobajo, 2020
- Species Nitzschia fenestrata Mereschkowsky, 1902-1903
- Species Nitzschia ferox Hustedt, 1952
- Species Nitzschia ferrazae Cholnoky, 1968
- Species Nitzschia fibulacomposita Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia fibula-fissa Lange-Bertalot, 1980
- Species Nitzschia filia Skvortzov, 1976
- Species Nitzschia filiformis (W.Smith) Hustedt
- Species Nitzschia filiformis Hajós, 1959
- Species Nitzschia fina Frenguelli, 1938
- Species Nitzschia firthii Fuge, 1937
- Species Nitzschia flexa Schumann, 1862
- Species Nitzschia flexella Suringar, 1867 (1868)
- Species Nitzschia flexella Brébisson ex Chase in Habirshaw, 1885 (1877-1894)
- Species Nitzschia flexella Suringar, 1867
- Species Nitzschia flexoides Geitler, 1968
- Species Nitzschia fluminensis Grunow
- Species Nitzschia fluorescens B.E.Volcani & C.-W.Li
- Species Nitzschia fluvialis Patrick & Freese, 1961
- Species Nitzschia fogedi M. Möller, 1950
- Species Nitzschia fonticola (Grunow) Grunow, 1881
- Species Nitzschia fonticola Grunow, 1879 accepted as Nitzschia palea var. fonticola Grunow, 1879
- Species Nitzschia fonticoloides Sovereign, 1960
- Species Nitzschia fontifuga Cholnoky, 1962
- Species Nitzschia forfica Cholnoky, 1968
- Species Nitzschia formica Hantzsch in Rabenhorst, 1863
- Species Nitzschia formosa Østrup, 1895
- Species Nitzschia fossalis Hustedt, 1942
- Species Nitzschia fossilis (Grunow) Grunow, 1881 accepted as Nitzschia amphibia var. fossilis Grunow, 1880
- Species Nitzschia fragilariiformis Compère, 1986
- Species Nitzschia fragilarioides Grunow in Cleve & Grunow, 1880
- Species Nitzschia franconica Reinsch, 1866
- Species Nitzschia fraudulenta Cleve, 1897
- Species Nitzschia frauenfeldii Grunow, 1862 accepted as Nitzschia amphibia f. frauenfeldii (Grunow) Lange-Bertalot, 1987
- Species Nitzschia fremontensis Lohman & Andrews, 1968
- Species Nitzschia frequens Hustedt, 1957
- Species Nitzschia frickei Reichelt ex Hustedt in Schmidt et al., 1922
- Species Nitzschia frigida Grunow, 1880
- Species Nitzschia frustuloides Manguin
- Species Nitzschia frustulum (Kützing) Grunow, 1880
- Species Nitzschia fruticosa Hustedt, 1957
- Species Nitzschia fundi Cholnoky, 1968
- Species Nitzschia fusidium H.L. Smith, 1874-1879
- Species Nitzschia fusiformis Grunow in Cleve & Grunow, 1880
- Species Nitzschia fusoides Ehrlich, 1975
- Species Nitzschia fussiformis Pantocsek, 1902
- Species Nitzschia fussioides Pantocsek, 1913
- Species Nitzschia fusulata Kufferath, 1956
- Species Nitzschia gaarderi Hasle, 1960
- Species Nitzschia gaertneriae Lange-Bertalot & Metzeltin, 1996
- Species Nitzschia galinarum Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia gallica (Brun in Héribaud) Pantocsek, 1902 accepted as Nitzschia vitrea f. gallica Brun in Héribaud, 1893
- Species Nitzschia gandersheimiensis Krasske, 1927
- Species Nitzschia gaoi Bing Liu, S.Blanco & B.Q.Huang, 2015
- Species Nitzschia garrensis Hustedt, 1950
- Species Nitzschia gastroides Swirenko, 1941
- Species Nitzschia gazellae Karsten, 1905
- Species Nitzschia geitleri Hustedt, 1959
- Species Nitzschia gelida Grunow
- Species Nitzschia geniculata Hustedt, 1928
- Species Nitzschia genkalii Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia gentilis
- Species Nitzschia germanica (Richter) M. Peragallo, 1903 accepted as Homoeocladia germanica Richter, 1879
- Species Nitzschia gessneri Hustedt, 1953
- Species Nitzschia ghanaensis Foged, 1966
- Species Nitzschia gibba Rauschenbach, 1921
- Species Nitzschia gieskesii Cholnoky, 1963
- Species Nitzschia gigantea (Ehrenberg) Ralfs in Pritchard, 1861 accepted as Synedra gigantea Ehrenberg, 1840
- Species Nitzschia gisela Lange-Bertalot, 1987
- Species Nitzschia glaberrima Østrup, 1918
- Species Nitzschia glabra Østrup, 1913
- Species Nitzschia glacialis Grunow
- Species Nitzschia glandiformis Hustedt in Schmidt et al., 1924
- Species Nitzschia gobbii Accoroni, Romagnoli, Giulietti & Totti in Giuletti et al., 2021
- Species Nitzschia goetzeana Otto Müller accepted as Aulacoseira goetzeana (Otto Müller) Simonsen, 1979
- Species Nitzschia goteborgensis Aleem, 1973
- Species Nitzschia gotlandica A.Cleve, 1952
- Species Nitzschia gracilenta (Grunow ex Juhlin-Dannfelt)
- Species Nitzschia gracilenta Grunow in Brébisson, 1870
- Species Nitzschia graciliformis Lange-Bertalot & Simonsen, 1978
- Species Nitzschia gracilis Hantzsch, 1860
- Species Nitzschia gracilis (Brébisson in Kützing)
- Species Nitzschia gracilis Brébisson ex H.L. Smith, 1874-1879
- Species Nitzschia gracillima Heiden & Kolbe, 1928
- Species Nitzschia gracilloides Hustedt, 1953
- Species Nitzschia graciloides Gandhi, 1970
- Species Nitzschia graciloides Hustedt, 1959
- Species Nitzschia gradifera Hustedt, 1922
- Species Nitzschia graeffii Grunow ex Cleve, 1878 accepted as Tryblionella graeffii (Grunow ex Cleve) D.G.Mann, 1990
- Species Nitzschia grana M.H.Hohn & Hellerman, 1966
- Species Nitzschia grandis Kitton, 1874
- Species Nitzschia granii G.R.Hasle, 1964
- Species Nitzschia granulata Grunow, 1880
- Species Nitzschia granulosa Leuduger-Fortmorel, 1879
- Species Nitzschia grigoriewi Mereschkowsky, 1906
- Species Nitzschia grigoriewi Mereschkowsky, 1906
- Species Nitzschia groenlandica Østrup, 1897
- Species Nitzschia grossepunctata Schrader, 1976
- Species Nitzschia grossestriata Hustedt, 1955
- Species Nitzschia groveana
- Species Nitzschia grovei Grunow, 1888
- Species Nitzschia grovei De Toni & Levi-Morenos, 1889
- Species Nitzschia gruendleri Grunow
- Species Nitzschia grunowii Hasle, 1972
- Species Nitzschia guadalupensis Manguin, 1952
- Species Nitzschia guamensis Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia guineensis Hustedt in Schmidt et al., 1922
- Species Nitzschia guttula Schrader in Schrader & Fenner, 1976
- Species Nitzschia gyrosigma Ohtsuka, 2005
- Species Nitzschia habirshawii Febiger ex H.L.Smith, 1879
- Species Nitzschia hachiroensis H. Kobayasi in Kobayasi et al., 1977
- Species Nitzschia hadriatica Lange-Bertalot, 1997
- Species Nitzschia halloyii Maidana & Herbst, 1989
- Species Nitzschia haloserbica Vidaković, Ector, C.E.Wetzel & Krizmanić in Vidaković et al., 2022
- Species Nitzschia halteriformis Hustedt, 1952
- Species Nitzschia hamata (W. Smith) De Toni, 1892 accepted as Synedra hamata W.Smith, 1853
- Species Nitzschia hankensis Skvortzow, 1929
- Species Nitzschia hantanense L.Tan & B.H.Kim in Tan et al., 2020
- Species Nitzschia hantanii L. Tan & B.H. Kim
- Species Nitzschia hantzschiaeformis
- Species Nitzschia hantzschiana Rabenhorst, 1860
- Species Nitzschia hantzschianobaicalis Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia harderi Hustedt, 1948
- Species Nitzschia harrisonii Cholnoky, 1960
- Species Nitzschia haslea Schoeman in Schoeman & Meaton, 1982
- Species Nitzschia hassiaca Krasske, 1932
- Species Nitzschia hastata Skvortzow, 1971
- Species Nitzschia heideni
- Species Nitzschia heimii (Manguin) Hasle, 1965 accepted as Pseudonitzschia heimii Manguin, 1960
- Species Nitzschia helleri Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia hemistriata Hagelstein, 1939
- Species Nitzschia heteropolica Schrader, 1973
- Species Nitzschia heufleriana Grunow, 1862
- Species Nitzschia hevesensis Pantocsek, 1889
- Species Nitzschia hexagonata
- Species Nitzschia hiemalis Hustedt, 1943
- Species Nitzschia hiengheneana Manguin ex Kociolek & Reviers, 1996
- Species Nitzschia hierosolymitana D.G.Mann, 1980
- Species Nitzschia hoehnkii Hustedt, 1959
- Species Nitzschia hollerupensis Foged, 1962
- Species Nitzschia holsatica Hustedt, 1930
- Species Nitzschia homburgiensis Lange-Bertalot, 1978
- Species Nitzschia homoeocladia Heiberg, 1863
- Species Nitzschia hondoensis Hanna & Grant, 1926
- Species Nitzschia hongkongensis Skvortzov, 1975
- Species Nitzschia hudsonii Poulin & Cardinal, 1983
- Species Nitzschia hulensis Sherman & Patrick, 1981
- Species Nitzschia hummii Hustedt, 1955
- Species Nitzschia hungarica Grunow, 1862 accepted as Tryblionella hungarica (Grunow) Frenguelli, 1942
- Species Nitzschia huniensis Foged, 1966
- Species Nitzschia hustedti Debes ex Hustedt in Schmidt et al., 1924
- Species Nitzschia hustedtiana Salah, 1953
- Species Nitzschia hustedtiana Cholnoky, 1959
- Species Nitzschia hustedtiana Hustedt, 1959
- Species Nitzschia hustedtii Sheshukova in Proschkina-Lavrenko, 1950
- Species Nitzschia hustedtii Sheshukova in Poretzky & Sheshukova, 1953
- Species Nitzschia hyalina Gregory, 1857
- Species Nitzschia hyalina Jurilj, 1957
- Species Nitzschia hyalina (Grunow in Van Heurck; Grunow) F.W. Mills, 1934 accepted as Hantzschia hyalina Grunow, 1884
- Species Nitzschia hybrida Grunow
- Species Nitzschia hybridaeformis Hustedt, 1955
- Species Nitzschia hyperborea
- Species Nitzschia ignimontana Brun & Héribaud in Héribaud, 1893
- Species Nitzschia ignorata Krasske, 1929 accepted as Nitzschia nana Grunow, 1881
- Species Nitzschia ikeanae Fryxell & Lee in Lee & Fryxell, 1996
- Species Nitzschia iltisii Compère, 1975
- Species Nitzschia imae Ãlvarez-Blanco & S.Blanco, 2013
- Species Nitzschia immunda Archibald, 1966
- Species Nitzschia imperforata Andrews, 1980
- Species Nitzschia impressa Hustedt, 1954
- Species Nitzschia improvisa Simonsen, 1960
- Species Nitzschia incerta (Grunow) M.Peragallo, 1903 accepted as Nitzschia lorenziana var. incerta Grunow in Cleve & Grunow, 1880
- Species Nitzschia incognita Legler & Krasske, 1940
- Species Nitzschia incolor Mereschkowsky, 1902
- Species Nitzschia incomptus Hohn & Hellerman, 1963
- Species Nitzschia inconspicua Grunow, 1862
- Species Nitzschia incrustans Grunow, 1862
- Species Nitzschia incurva Grunow, 1878
- Species Nitzschia indica Schrader, 1974
- Species Nitzschia indica Karsten, 1907
- Species Nitzschia indistincta Michailov, 1984
- Species Nitzschia inducta Hustedt, 1952
- Species Nitzschia inflata Kufferath, 1957
- Species Nitzschia inflatula G.R.Hasle, 1974
- Species Nitzschia ingens Frenguelli, 1945
- Species Nitzschia ingenua Hustedt, 1935
- Species Nitzschia inimasta Carter & Denny, 1982
- Species Nitzschia innominata Sovereign, 1958
- Species Nitzschia insecta Hustedt, 1942
- Species Nitzschia insignis Gregory, 1857
- Species Nitzschia intercedens Grunow, 1878
- Species Nitzschia interfrigidaria McCollum, 1975
- Species Nitzschia interfrigidaria McColloum emend Ciesielski, 1983
- Species Nitzschia intermedia Hantzsch ex Cleve & Grunow, 1880
- Species Nitzschia intermediopsis Simonsen, 1987
- Species Nitzschia intermissa Hustedt, 1949
- Species Nitzschia interrupta (Grunow in Cleve) Meister, 1932 accepted as Nitzschia weissflogii var. interrupta Cleve, 1878
- Species Nitzschia interrupta Heiden & Kolbe, 1928
- Species Nitzschia interruptestriata Simonsen, 1974
- Species Nitzschia inversa Grunow in Cleve & Möller, 1879
- Species Nitzschia invicta Hustedt
- Species Nitzschia invisa Schrader, 1973
- Species Nitzschia invisitata Hustedt, 1942
- Species Nitzschia iranica Compère, 1981
- Species Nitzschia irregularis R.Ross & Abdin, 1949
- Species Nitzschia irremissa Cholnoky, 1959
- Species Nitzschia irrepta Hustedt, 1942
- Species Nitzschia irresoluta Hustedt, 1942
- Species Nitzschia irritans Cholnoky, 1961
- Species Nitzschia islandica Østrup, 1918
- Species Nitzschia italica (Rabenhorst) Ralfs in Pritchard, 1861 accepted as Sigmatella italica Rabenhorst, 1853
- Species Nitzschia iugiformis Hustedt, 1922
- Species Nitzschia jalgaonensis Sarode & Kamat, 1984
- Species Nitzschia jamiesoni Barber & Carter, 1972
- Species Nitzschia janei Salah, 1955
- Species Nitzschia janischii Grunow, 1880
- Species Nitzschia januaria Schrader, 1976
- Species Nitzschia japonica Skvortzow, 1932
- Species Nitzschia japonica Meister, 1937
- Species Nitzschia javanica Grunow in Cleve & Möller, 1878
- Species Nitzschia jelineckiana Grunow, 1867
- Species Nitzschia jelineckii Grunow, 1863 accepted as Tryblionella jelineckii (Grunow) D.G.Mann, 1990
- Species Nitzschia jeniseyensis Skvortzow, 1971
- Species Nitzschia johnmartinii Fryxell & Kaczmarska, 1994
- Species Nitzschia johorensis Suriyanti & Usup, 2017
- Species Nitzschia jonssoni Østrup, 1918
- Species Nitzschia jordanii Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia jouseae Burckle, 1972
- Species Nitzschia jouseana Skvortzow, 1971
- Species Nitzschia jucunda Hustedt, 1945
- Species Nitzschia jugata Gandhi, 1955
- Species Nitzschia jugiformis Hustedt, 1922
- Species Nitzschia kahlii H. Lange-Bertalot & Rumrich in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia kaikonkiensis Woodhead & Tweed, 1960
- Species Nitzschia kalganica Skvortzov, 2012
- Species Nitzschia kanakarum Gerd Moser
- Species Nitzschia kanayae T.V. Desikachary & S. Gowthaman in T.V. Desikachary, 1989
- Species Nitzschia kanayai Desikachary & Gowthaman in Desikachary, 1989
- Species Nitzschia kanayensis Schrader, 1974
- Species Nitzschia kapimbiense Kufferath, 1956
- Species Nitzschia karrooensis Cholnoky, 1959
- Species Nitzschia kavirondoensis L.Sitoki & E.Rott, 2013
- Species Nitzschia kenaiensis Stone in McLaughlin & Stone, 1986
- Species Nitzschia kerguelensis (O'Meara) Hasle, 1965 accepted as Terebraria kerguelensis E.O'Meara, 1876 †
- Species Nitzschia khursevichae Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia kimberliensis M. Potapova in Potapova, M. & Charles, D.F., 2004
- Species Nitzschia kisselewii Skvortzow, 1971
- Species Nitzschia kittlii Grunow, 1882
- Species Nitzschia kittoni H.L. Smith, 1878
- Species Nitzschia kittonii H.L. Smith, 1878
- Species Nitzschia kleinteichiana Hamsher et al., 2016
- Species Nitzschia knysnensis Cholnoky, 1963
- Species Nitzschia kociolekii Alakananda, B.Karthick, J.C.Taylor & P.B.Hamilton, 2015
- Species Nitzschia koehleri Lauby, 1910
- Species Nitzschia kolaczeckii Grunow, 1867
- Species Nitzschia kolaczekii Grunow, 1867
- Species Nitzschia kolaizeckii Grunow, 1877
- Species Nitzschia kotschii (Grunow) F.W. Mills, 1934 accepted as Homoeocladia kotschyi Grunow, 1878
- Species Nitzschia kowiensis Giffen, 1970
- Species Nitzschia krachiensis Foged, 1966
- Species Nitzschia krenicola Cholnoky, 1963
- Species Nitzschia kryophila Cleve, 1883
- Species Nitzschia kryophila Cleve in Cleve & Moller, 1882
- Species Nitzschia krysnensis Cholnoky, 1963
- Species Nitzschia kuetzingiana Hilse, 1863
- Species Nitzschia kuetzingii Rabenhorst, 1864
- Species Nitzschia kuetzingioides Hustedt, 1959
- Species Nitzschia kufferathii Woodhead & Tweed, 1960
- Species Nitzschia kurzeana Rabenhorst, 1873
- Species Nitzschia kurzii Rabenhorst in Grunow, 1880
- Species Nitzschia labella Gerd Moser
- Species Nitzschia labuensis Cleve, 1883
- Species Nitzschia lacessens Cholnoky, 1968
- Species Nitzschia lacrima Gersonde, 1991
- Species Nitzschia lacuna Patrick & Freese, 1961
- Species Nitzschia lacunarum Hustedt, 1930
- Species Nitzschia lacunensis Cholnoky, 1968
- Species Nitzschia lacunicola Patrick & Freese, 1961
- Species Nitzschia lacuskarluki Manguin, 1960
- Species Nitzschia lacus-karluki Manguin ex Kociolek & Reviers, 1996
- Species Nitzschia lacustris Hustedt in A. Schmidt, 1922
- Species Nitzschia lacuum Lange-Bertalot, 1980
- Species Nitzschia laevis Hustedt, 1939
- Species Nitzschia laevis Frenguelli, 1923
- Species Nitzschia laevissima Grunow in Cleve, 1883
- Species Nitzschia lagunae Cholnoky, 1960
- Species Nitzschia lagunensis Martinez-Goss, 1997
- Species Nitzschia lahusenii Pantocsek, 1902
- Species Nitzschia lamprocampa Hantzsch ex Cleve & Grunow
- Species Nitzschia lanceola Grunow
- Species Nitzschia lanceolata W.Smith, 1853
- Species Nitzschia lanceolata 'Donahue' Abbott, 1974
- Species Nitzschia lancettula O.F.Müller
- Species Nitzschia lancettuloides Hustedt, 1956
- Species Nitzschia lange-bertalotii Coste & Ricard, 1982
- Species Nitzschia lascrucensis Lobban & C.E.Wetzel in Lobban et al., 2019
- Species Nitzschia lata O. Witt, 1873
- Species Nitzschia latens Hustedt, 1949
- Species Nitzschia latestriata (Brébisson ex Kützing) Ralfs, 1861 accepted as Scoliotropis latestriata (Brébisson ex Kützing) Cleve, 1894
- Species Nitzschia latifasciata Patrick, 1946
- Species Nitzschia latifibulata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia latiuscula Grunow in Van Heurck, 1881
- Species Nitzschia latofasciata Skvortzow, 1946
- Species Nitzschia lauenburgiana Hustedt, 1950
- Species Nitzschia lawsonii Foged, 1966
- Species Nitzschia lecointei van Heurck, 1909
- Species Nitzschia leehyi G. Fryxell, 2000
- Species Nitzschia legleri Hustedt, 1959
- Species Nitzschia leistikowii Lange-Bertalot, 1980
- Species Nitzschia lejartii Amossé, 1969
- Species Nitzschia lentiformis Mikhailov, 1981
- Species Nitzschia lepotieri Amossé, 1969
- Species Nitzschia lesbia Cholnoky, 1963
- Species Nitzschia lesinensis Grunow, 1880
- Species Nitzschia lesothensis Schoeman, 1973
- Species Nitzschia leucosigma Benecke, 1900
- Species Nitzschia levandensis
- Species Nitzschia levidensis (W.Smith) Grunow, 1881 accepted as Tryblionella levidensis W.Smith, 1856
- Species Nitzschia levis Frenguelli, 1923
- Species Nitzschia levissima Grunow in Cleve & Möller, 1882
- Species Nitzschia liebethruthii Rabenhorst, 1864
- Species Nitzschia liebetruthii Rabenhorst, 1864 accepted as Nitzschia liebethruthii Rabenhorst, 1864
- Species Nitzschia ligeriana H. Peragallo in Tempère & Peragallo, 1908
- Species Nitzschia ligowskii Witkowski, Lange-Bertalot, Kociolek & Brzezinska, 2004
- Species Nitzschia limes Pantocsek, 1902
- Species Nitzschia limi Frenguelli, 1926
- Species Nitzschia limicola Grunow, 1880
- Species Nitzschia limulus Hohn & Hellerman, 1963
- Species Nitzschia linearis W.Smith, 1853
- Species Nitzschia lineata (Castracane) Hasle, 1972
- Species Nitzschia lineata Grunow, 1878
- Species Nitzschia lineola Cleve, 1897
- Species Nitzschia lineolata Grunow in Cleve & Möller, 1879
- Species Nitzschia linkei Hustedt, 1939
- Species Nitzschia lionella Cholnoky, 1960
- Species Nitzschia littoralis Grunow, 1880 accepted as Tryblionella littoralis (Grunow) D.G.Mann, 1990
- Species Nitzschia littorea Grunow, 1881
- Species Nitzschia lobata Meunier, 1910
- Species Nitzschia loczyi Pantocsek, 1889
- Species Nitzschia lodicula Kaczmarska, 1986
- Species Nitzschia longa Grunow accepted as Bacillaria longa (Grunow) De Toni, 1892
- Species Nitzschia longabaicalis Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia longicollum Hasle
- Species Nitzschia longirostris Hustedt, 1937
- Species Nitzschia longissima (Brébisson) Ralfs, 1861
- Species Nitzschia lorenziana Grunow, 1879
- Species Nitzschia lubrica (Meneghini manuscript) M. Peragallo, 1903 accepted as Schizonema lubricum Meneghini ex Kutzing, 1844
- Species Nitzschia lucida Meister, 1937
- Species Nitzschia lucisensibilis B.E.Volcani & C.-W.Li
- Species Nitzschia lurida Cholnoky, 1961
- Species Nitzschia luzonensis Hustedt
- Species Nitzschia macaronesica Lange-Bertalot, 1993
- Species Nitzschia macedonica Hustedt, 1945
- Species Nitzschia macera Hustedt, 1958
- Species Nitzschia machardyae H. Lange-Bertalot & Rumrich in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia macilenta Gregory
- Species Nitzschia macrogongyla Hantzsch ex Rabenhorst, 1848-1860
- Species Nitzschia maeotica Pantocsek, 1902
- Species Nitzschia magnacarina M.H.Hohn & J.Hellerman, 1966
- Species Nitzschia magnopunctata Poretzsky, 1953
- Species Nitzschia maharashtrensis Sarode & Kamat, 1984
- Species Nitzschia mahihaensis Foged, 1959
- Species Nitzschia maiae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia maillardii Coste & Ricard, 1982
- Species Nitzschia major Grunow, 1881 accepted as Hantzschia amphioxys f. major Grunow in Van Heurck, 1881
- Species Nitzschia majuscula Grunow
- Species Nitzschia makarovae Mikhailov, 1984
- Species Nitzschia maleinterpretaria Schrader, 1976
- Species Nitzschia mamataensis Foged, 1966
- Species Nitzschia mammalifera Kufferath, 1956
- Species Nitzschia mammalis Castracane, 1886
- Species Nitzschia manca Hustedt, 1957
- Species Nitzschia mancoides H.P. Gandhi, 1998 accepted as Nitzschia mancoides H.P.Gandhi ex Karthick, 2020
- Species Nitzschia mancoides H.P.Gandhi ex Karthick, 2020
- Species Nitzschia mangonicata Schoeman in Schoeman & Meaton, 1982
- Species Nitzschia manguini Maillard, 1962
- Species Nitzschia manguinii Cholnoky, 1968
- Species Nitzschia mankesimensis Foged, 1966
- Species Nitzschia mareei Kufferath, 1956
- Species Nitzschia marginata Hustedt, 1955
- Species Nitzschia marginifera Grunow in Cleve & Grunow, 1880
- Species Nitzschia marginulata Grunow, 1880
- Species Nitzschia marina Grunow, 1880
- Species Nitzschia martiana (C.Agardh) Van Heurck, 1896 accepted as Homoeocladia martiana var. martiana Agardh, 1827
- Species Nitzschia martini Krasske, 1939
- Species Nitzschia maxima Grunow in Van Heurck, 1881
- Species Nitzschia mccartneyi Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia media Hantzsch, 1860
- Species Nitzschia mediastalsis Hohn & Hellerman, 1963
- Species Nitzschia medioconstricta Hustedt, 1958
- Species Nitzschia mediocris Hustedt, 1949
- Species Nitzschia medioincrassata Vyverman, 1988
- Species Nitzschia mediterranea Hustedt, 1921
- Species Nitzschia meisteri Pantocsek, 1912
- Species Nitzschia meropeae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia mesiana Cholnoky, 1955
- Species Nitzschia mesolepta L.W. Bailey, 1861
- Species Nitzschia metzeltinii H. Lange-Bertalot in H. Lange-Bertalot & S.I. Genkal, 1999
- Species Nitzschia mianowicziae Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia microcephala Grunow, 1878
- Species Nitzschia microcephala auct. non Cleve & Grunow
- Species Nitzschia microcostata Hajós, 1959
- Species Nitzschia microrhynchus (Grunow)
- Species Nitzschia microsicula Kufferath, 1956
- Species Nitzschia migrans Cleve, 1897
- Species Nitzschia minima Meister, 1934 (1935)
- Species Nitzschia minuscula Frenguelli, 1938
- Species Nitzschia minuta Bleisch, 1863
- Species Nitzschia minuta Meister, 1932
- Species Nitzschia minutissima W.Smith, 1853
- Species Nitzschia minutula Grunow in Van Heurck, 1881
- Species Nitzschia miocenica Burckle, 1972
- Species Nitzschia mirabilis Cleve-Euler, 1952
- Species Nitzschia miramarensis Hagelstein, 1939
- Species Nitzschia miramaris Frenguelli, 1930
- Species Nitzschia miranda Giffen, 1984
- Species Nitzschia misellaburchanii Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia miserabilis Cholnoky, 1963
- Species Nitzschia mitchelliana Greenleaf
- Species Nitzschia modesta Hustedt, 1950
- Species Nitzschia moholensis Schrader, 1974
- Species Nitzschia moissacensis (Héribaud-Joseph) Comber, 1901 accepted as Grunowia solgensis (Cleve-Euler) M.Aboal, 2003
- Species Nitzschia molesta Manguin, 1964
- Species Nitzschia mollis Hustedt, 1952 accepted as Psammodictyon molle (Hustedt) D.G.Mann, 1990
- Species Nitzschia monachorum Lange-Bertalot, 1987
- Species Nitzschia mongolica Skvortzow, 1935
- Species Nitzschia monguilloni Manguin, 1942
- Species Nitzschia monoensis Kociolek & Herbst, 1992
- Species Nitzschia montanestris Camburn, 1978
- Species Nitzschia morosa Cholnoky, 1963
- Species Nitzschia mucronata Østrup, 1918
- Species Nitzschia mucronata Pantocsek, 1902
- Species Nitzschia multistriata Takano, 1993
- Species Nitzschia muranensis Cholnoky, 1961
- Species Nitzschia mytilicola Giffen, 1984
- Species Nitzschia nagbogensis Foged, 1966
- Species Nitzschia nagpurensis Sarode & Kamat, 1984
- Species Nitzschia nana Grunow, 1881
- Species Nitzschia nanoangustata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia nanodissipata Ch.Li & Witkowski in Witkowski et al., 2016
- Species Nitzschia natalensis Cholnoky, 1960
- Species Nitzschia natans H. Lange-Bertalot in K. Krammer & H. Lange-Bertalot, 1997
- Species Nitzschia nathorsti Brun, 1901
- Species Nitzschia navia Carter, 1966
- Species Nitzschia naviculaeformis Hustedt in Schmidt et al., 1922
- Species Nitzschia navicularis (Brébisson) Grunow, 1880 accepted as Tryblionella navicularis (Brébisson) Ralfs, 1861
- Species Nitzschia navis-varingica N.Lundholm & Ø.Moestrup, 2000
- Species Nitzschia navrongensis Foged, 1966
- Species Nitzschia neglecta Hustedt, 1958
- Species Nitzschia nelsoni Hanna & Grant, 1926
- Species Nitzschia neocaledonica Manguin ex Kociolek & Reviers, 1996
- Species Nitzschia neoconstricta T.V.Desikachary, S.Gowthaman & Y.Latha, 1987
- Species Nitzschia neofrigida L.K. Medlin in Medlin & Hasle, 1990
- Species Nitzschia neogena Grunow, 1882
- Species Nitzschia neogenica Zanon, 1933
- Species Nitzschia neotropica H. Lange-Bertalot & Rumrich in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia neptuni (Schumann) M. Peragallo, 1903 accepted as Tryblionella neptunii Schumann, 1867
- Species Nitzschia nereidis Cholnoky, 1960
- Species Nitzschia nevrovae Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia ngoziensis Otto Müller, 1905
- Species Nitzschia nicobarica (Grunow) Grunow
- Species Nitzschia nienhuisii Sterrenburg & Sterrenburg, 1990
- Species Nitzschia nikitiniana Skvortzov, 1937
- Species Nitzschia nollothae Giffen, 1984
- Species Nitzschia normanii Van Heurck, 1880-1885
- Species Nitzschia norvegica Hasle, 1964
- Species Nitzschia notabilis (Grunow) Grunow
- Species Nitzschia notata (Kützing) Rabenhorst ex M. Peragallo, 1903 accepted as Synedra notata Kützing, 1844
- Species Nitzschia notata (Kützing) Rabenhorst, 1863 accepted as Synedra notata Kützing, 1844
- Species Nitzschia novaeguineae Cholnoky, 1963
- Species Nitzschia novae-guineaensis Reichardt, 1988
- Species Nitzschia novaehollandiae Grunow in Cleve & Grunow, 1880
- Species Nitzschia novae-zelandia Inglis, 1881
- Species Nitzschia novazealandia Inglis, 1881
- Species Nitzschia nunguaensis Foged, 1966
- Species Nitzschia nuwukiana Patrick & Freese, 1961
- Species Nitzschia nyassensis O.F.Müller, 1905
- Species Nitzschia nystroemii Grunow in Cleve & Möller, 1879
- Species Nitzschia oamaruensis Schrader, 1969
- Species Nitzschia oberheimiana Rumrich & H. Lange-Bertalot in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia obesa Castracane, 1886
- Species Nitzschia obligata Archibald, 1966
- Species Nitzschia obliquecostata (Van Heurck) Hasle, 1972 accepted as Fragilaria obliquecostata f. obliquecostata Van Heurck, 1909
- Species Nitzschia oblonga Mikhailov, 1983
- Species Nitzschia oblonga L.W. Bailey, 1861
- Species Nitzschia oblongella Østrup, 1910
- Species Nitzschia obscura Grunow in Cleve & Grunow, 1880
- Species Nitzschia obscurepunctata Hustedt, 1987
- Species Nitzschia obsidialis Hustedt, 1949
- Species Nitzschia obsoleta Hustedt, 1949
- Species Nitzschia obsoletiformis Cholnoky, 1966
- Species Nitzschia obtusa W.Smith, 1853
- Species Nitzschia obtusangula Hustedt, 1950
- Species Nitzschia obtusa-schweinfurthii Grunow
- Species Nitzschia obtusata Grunow
- Species Nitzschia oceanica Hasle, 1960
- Species Nitzschia ocellata Cleve, 1881
- Species Nitzschia oestrupii Pantocsek, 1912
- Species Nitzschia ofinensis Foged, 1966
- Species Nitzschia ogivalis Kufferath, 1957
- Species Nitzschia okamurae Skvortzow, 1932
- Species Nitzschia okamurae Skvortzow, 1937
- Species Nitzschia olgae Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia oliffii Cholnoky, 1956
- Species Nitzschia olivieri Manguin, 1954
- Species Nitzschia omanensis Barkia I. & Ch. Li, 2019
- Species Nitzschia omega Hustedt, 1958
- Species Nitzschia omissa Skvortzov, 1975
- Species Nitzschia oregona Sovereign, 1963
- Species Nitzschia oscilla Carter, 1966
- Species Nitzschia osmophila Cholnoky, 1963
- Species Nitzschia ossiformis (Taylor) Simonsen, 1974 accepted as Synedra ossiformis Taylor, 1967
- Species Nitzschia ostenfeldi Hustedt, 1922
- Species Nitzschia ostenfeldii Hustedt
- Species Nitzschia ostii Konig, 1959
- Species Nitzschia ovalis H.J.Arnott, 1880
- Species Nitzschia oxyrhynchus Frenguelli, 1925
- Species Nitzschia paaschei Hasle, 1965
- Species Nitzschia pacifica Cupp, 1943
- Species Nitzschia paeneperpetua D.G. Mann, 1981
- Species Nitzschia palea (Kützing) W.Smith, 1856
- Species Nitzschia paleacea Grunow in Van Heurck, 1881
- Species Nitzschia paleaeformis Hustedt, 1950
- Species Nitzschia paleoides Hustedt, 1938
- Species Nitzschia palmida Carter, 1966
- Species Nitzschia palustris Hustedt, 1934
- Species Nitzschia pamirensis Hustedt in A. Schmidt, 1922
- Species Nitzschia panduriformis W.Gregory, 1857 accepted as Psammodictyon panduriforme (W.Gregory) D.G.Mann, 1990
- Species Nitzschia panduriformis sensu Hustedt in Schmidt et al., 1921
- Species Nitzschia pantocseki Hajós, 1968
- Species Nitzschia pantocsekii M. Peragallo, 1903
- Species Nitzschia papillosa Bertolli, Talgatti & Torgan, 2016
- Species Nitzschia paradoxa (J.F.Gmelin) Grunow, 1880 accepted as Bacillaria paxillifera (O.F.Müller) T.Marsson, 1901
- Species Nitzschia parallela Hustedt, 1955
- Species Nitzschia pararostrata (H.Lange-Bertalot) H.Lange-Bertalot, in Nevo & Wasser, 2000
- Species Nitzschia parkii D.G.Mann & Trobajo, 2014
- Species Nitzschia partita Hustedt, 1952
- Species Nitzschia parvula W.Smith, 1853
- Species Nitzschia parvula Lewis, 1862
- Species Nitzschia parvuloides Cholnoky
- Species Nitzschia pavida Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia pavini Manguin, 1954
- Species Nitzschia paxillifer (O.F.Müller) Heiberg, 1863 accepted as Bacillaria paxillifera (O.F.Müller) T.Marsson, 1901
- Species Nitzschia pecten Brun, 1880
- Species Nitzschia peisonis Pantocsek, 1912
- Species Nitzschia pekinensis Skvortzow, 1929
- Species Nitzschia pelagica G.Karsten, 1905
- Species Nitzschia pelagica Otto Müller, 1905
- Species Nitzschia pellucida Grunow, 1880
- Species Nitzschia pennata Tempère & Brun in Brun & Tempère, 1889
- Species Nitzschia peragalli Hasle, 1965 accepted as Fragilariopsis peragallii (Hasle) Cremer, 2003
- Species Nitzschia peragallii Hasle, 1965
- Species Nitzschia percuriosa Giffen, 1980
- Species Nitzschia perindistincta Cholnoky, 1960
- Species Nitzschia perlonga Pantocsek, 1902
- Species Nitzschia perminuta (Grunow) M.Peragallo, 1903
- Species Nitzschia perpusilla Rabenhorst, (1861)1864
- Species Nitzschia perpusilla Grunow, 1862
- Species Nitzschia perspicillata Camburn, 1978
- Species Nitzschia perspicua Cholnoky, 1960
- Species Nitzschia perspicua Sovereign, 1963
- Species Nitzschia persuadens Cholnoky, 1961
- Species Nitzschia pertenuis Frenguelli & Orlando, 1959
- Species Nitzschia pertica Hohn & Hellermann, 1963
- Species Nitzschia peruviana Manguin, 1964
- Species Nitzschia perversa Grunow, 1880
- Species Nitzschia petitiana Grunow, 1880
- Species Nitzschia petulla Carter, 1966
- Species Nitzschia philippina Skvortzow, 1937
- Species Nitzschia philippinarum Hustedt, 1942
- Species Nitzschia pilum Hustedt, 1942
- Species Nitzschia pinguescens Cholnoky, 1963
- Species Nitzschia pisca Patrick & Freese, 1961
- Species Nitzschia piscinarum Hustedt, 1948
- Species Nitzschia pistilla Carter, 1966
- Species Nitzschia plana W.Smith, 1853
- Species Nitzschia planctonica Hustedt in Schmidt et al., 1922
- Species Nitzschia plenus-venter Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia plicata Norman in H.L. Smith, 1874-1879
- Species Nitzschia plicatula Hustedt, 1953
- Species Nitzschia pliocena (Brun) Mertz, 1966 accepted as Fragilaria pliocena var. pliocena Brun, 1891
- Species Nitzschia pliocena (Brun) Wornardt, 1967 accepted as Fragilaria pliocena var. pliocena Brun, 1891
- Species Nitzschia plioveterana H. Lange-Bertalot in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000
- Species Nitzschia polaris Grunow ex Cleve, 1883
- Species Nitzschia polymorpha T.Marsson, 1900
- Species Nitzschia ponciensis R.Hagelstein, 1938
- Species Nitzschia poretzkyi Skvortzow, 1971
- Species Nitzschia porteri Frenguelli, 1949 †
- Species Nitzschia portulata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia praecurta Gersonde, 1991
- Species Nitzschia praefossilis Schrader, 1973
- Species Nitzschia praeinterfrigidaria McCollum, 1975
- Species Nitzschia praeinterfrigidaria McCollum emend Ciesielski, 1983
- Species Nitzschia praelonga Cleve, 1881
- Species Nitzschia praereinholdii Schrader, 1973
- Species Nitzschia pretoriensis Cholnoky, 1957
- Species Nitzschia princeps Hanna & Grant, 1926
- Species Nitzschia procera Hustedt, 1955
- Species Nitzschia procerabaicalis Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia proceroides Giffen, 1973
- Species Nitzschia producta Comber in G. Murray, 1903
- Species Nitzschia profunda Kufferath, 1956
- Species Nitzschia prolongat Manguin, 1960
- Species Nitzschia prolongata Hustedt, 1938
- Species Nitzschia prolongata Manguin, 1957
- Species Nitzschia prolongata Kazarina, 1978
- Species Nitzschia prolongatoides G.R.Hasle, 1965
- Species Nitzschia promare Medlin, 1990
- Species Nitzschia propinqua T.Marsson, 1900
- Species Nitzschia proschkina-lavrenkoi Skvortzow, 1971
- Species Nitzschia proshkina-lavrenki Aleem, 1973
- Species Nitzschia protuberans Brun in Brun & Tempère, 1889
- Species Nitzschia proxima Hustedt, 1955
- Species Nitzschia pseudepiphytica Cocquyt & M.deHaan, 2012
- Species Nitzschia pseudoaequalis Cocquyt in Cocquyt & Ryken, 2017
- Species Nitzschia pseudoamphibia
- Species Nitzschia pseudoamphioxoides Gandhi, 1964
- Species Nitzschia pseudoamphioxys Hustedt, 1942
- Species Nitzschia pseudoatomus Stoermer, 1963
- Species Nitzschia pseudobacata Cholnoky, 1958
- Species Nitzschia pseudocapitata Desikachary & Gowthaman in Desikachary, 1989
- Species Nitzschia pseudocarinata Cholnoky, 1970
- Species Nitzschia pseudocommunis Hustedt, 1939
- Species Nitzschia pseudocylindrica Schrader in Schrader & Fenner, 1976
- Species Nitzschia pseudodelicatissima Hasle, 1976
- Species Nitzschia pseudofonticola Hustedt, 1942
- Species Nitzschia pseudofossilis Gandhi, 1959
- Species Nitzschia pseudogracilis Gandhi, 1959
- Species Nitzschia pseudohungarica Hustedt, 1939
- Species Nitzschia pseudohybrida Hustedt, 1955
- Species Nitzschia pseudokerguelensis Schrader, 1976
- Species Nitzschia pseudolinearis Gaud, 1974
- Species Nitzschia pseudonana Hasle, 1974
- Species Nitzschia pseudopectinalis Kufferath, 1957
- Species Nitzschia pseudoseriata G.R.Hasle, 1965 accepted as Pseudonitzschia australis Frenguelli, 1939
- Species Nitzschia pseudosigma Hustedt, 1937
- Species Nitzschia pseudosinuata P.B. Hamilton & K.R. Laird, 2001
- Species Nitzschia pseudostagnorum Hustedt, 1956
- Species Nitzschia pseudosubrostrata Kufferath, 1956
- Species Nitzschia pseudosuriella Gaud, 1974
- Species Nitzschia pseudotropica Guermeur, 1954
- Species Nitzschia pubens Cholnoky, 1960
- Species Nitzschia puella Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia puellula Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia pulchella Peragallo & Peragallo, 1899
- Species Nitzschia pulcherrima (Grunow ex Kitton) Grunow, 1878
- Species Nitzschia pulchra Hustedt, 1952
- Species Nitzschia pulchriora Giffen, 1980
- Species Nitzschia pumila Hustedt, 1954
- Species Nitzschia punae Frenguelli, 1936
- Species Nitzschia punctata (W.Smith) Grunow, 1878 accepted as Tryblionella punctata W.Smith, 1853
- Species Nitzschia punctata (W.Smith) Grunow, 1880 accepted as Tryblionella punctata W.Smith, 1853
- Species Nitzschia punctata L.W. Bailey, 1861
- Species Nitzschia punctata sensu Peragallo & Peragallo, 1899
- Species Nitzschia pungens Grunow ex Cleve, 1897
- Species Nitzschia pungiformis G.R.Hasle, 1971
- Species Nitzschia pura Hustedt, 1954
- Species Nitzschia puriformis Hlúbiková & Ector, 2009
- Species Nitzschia pusilla Grunow, 1862
- Species Nitzschia pusilla (Kützing) Lange-Bertalot, 1976
- Species Nitzschia pusilla Schrader, 1976
- Species Nitzschia pusilluhasta Lehmkuhl & C. Bicudo, 2019
- Species Nitzschia pustulata Meister, 1937
- Species Nitzschia putrida (Cohn) Benecke, 1900
- Species Nitzschia quadrangula (Kützing) Lange-Bertalot, 1980 accepted as Synedra quadrangula Kützing, 1844
- Species Nitzschia quarnerensis
- Species Nitzschia quickiana Hagelstein, 1939
- Species Nitzschia rabenhorstii Grunow, 1880
- Species Nitzschia radicula Hustedt, 1942
- Species Nitzschia radula W. Smith teste Arnott
- Species Nitzschia ralfsii Woodhead & Tweed, 1960
- Species Nitzschia rangoonensis Grunow ex Rabenhorst, 1873
- Species Nitzschia rauhii Manguin, 1964
- Species Nitzschia rautenbachiae Cholnoky, 1957
- Species Nitzschia recta Hantzsch ex Rabenhorst, 1862
- Species Nitzschia recta Grunow in Cleve & Grunow, 1880
- Species Nitzschia rectangulata Hustedt, 1952
- Species Nitzschia rectangulata Kufferath, 1957
- Species Nitzschia rectiformis Hustedt, 1943
- Species Nitzschia rectilonga Takano, 1983
- Species Nitzschia rectirobusta Lange-Bertalot in Lange-Bertalot & Metzeltin, 1996
- Species Nitzschia rectissima Hustedt, 1954
- Species Nitzschia regula Hustedt
- Species Nitzschia reguloides Cholnoky, 1954
- Species Nitzschia reimeri Fryxell & Kaczmarska, 1994
- Species Nitzschia reimerii Kociolek & Herbst, 1992
- Species Nitzschia reimersenii G. Fryxell & Kaczmarska, 1996
- Species Nitzschia reinhardii Alexeenko, 1931
- Species Nitzschia reinholdii Kanaya emend Barron & Baldauf, 1986 accepted as Nitzschia A.H. Hassall, 1845
- Species Nitzschia reinholdii du Saar & de Wolf, 1973
- Species Nitzschia rennellensis Foged, 1957
- Species Nitzschia retusa Lange-Bertalot & Bonik, 1976
- Species Nitzschia reversa W.Smith accepted as Nitzschia lorenziana var. incerta Grunow in Cleve & Grunow, 1880
- Species Nitzschia rhaetica (Meister) Coupin, 1930 (circa 1930) accepted as Hantzschia rhaetica Meister, 1912
- Species Nitzschia rhombica Hustedt, 1955
- Species Nitzschia rhombicolanceolata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia rhombicolancettula H.Lange-Bertalot & M.Werum, 2014
- Species Nitzschia rhombiformis M.Potapova, 2004
- Species Nitzschia rhopalodioides Hustedt, 1955
- Species Nitzschia richterae G.H.Schwabe & R.Simonsen, 1961
- Species Nitzschia riedelia Schrader, 1974
- Species Nitzschia rigida (Kützing) H.Peragallo & M.Peragallo
- Species Nitzschia rimosa Manguin in Bourrelly & Manguin, 1952
- Species Nitzschia ritscheri (Hustedt) Hasle, 1972 accepted as Fragilariopsis ritscheri Hustedt, 1958
- Species Nitzschia robusta Hustedt, 1949
- Species Nitzschia rochensis D. Metzeltin, H. Lange-Bertalot & F. García-Rodríguez, 2005
- Species Nitzschia rolandii Schrader, 1973
- Species Nitzschia romana Grunow, 1881 accepted as Nitzschia palea var. romana Grunow, 1880
- Species Nitzschia romanoides Manguin, 1952
- Species Nitzschia romanowiana Pantocsek, 1902
- Species Nitzschia rorida M.H.Giffen, 1975
- Species Nitzschia rosenstockii Lange-Bertalot, 1980
- Species Nitzschia rosentockii Lange-Bertalot, 1980
- Species Nitzschia rostellata Hustedt in Schmidt et al., 1922
- Species Nitzschia rostrata Grunow, 1880
- Species Nitzschia rotula Carter, 1966
- Species Nitzschia rousselinii Maillard, 1977
- Species Nitzschia ruda Cholnoky, 1968
- Species Nitzschia rufisquiana Guermeur, 1954
- Species Nitzschia rufitorrentis Cholnoky, 1960
- Species Nitzschia rufitorrentis Cholnoky, 1962
- Species Nitzschia rugosa Hustedt, 1935
- Species Nitzschia rugosa Østrup in Héribaud et al., 1920
- Species Nitzschia rupestris Proschkina-Lavrenko, 1963
- Species Nitzschia rusingae E.Rott & L.Sitoki, 2013
- Species Nitzschia rustica Frenguelli, 1953
- Species Nitzschia ruttneri Hustedt, 1938
- Species Nitzschia sakaensis Foged, 1966
- Species Nitzschia salina Sheshukova-Poretzkaya, 1955
- Species Nitzschia salina Sheshukova, 1956
- Species Nitzschia salinarum Grunow, 1881 accepted as Nitzschia vitrea var. salinarum Grunow, 1862
- Species Nitzschia salinicola Aleem & Hustedt, 1951
- Species Nitzschia salissigi Foged, 1951
- Species Nitzschia salpaespinosae Lange-Bertalot in Lange-Bertalot & Krammer, 1987
- Species Nitzschia salta Carter, 1966
- Species Nitzschia salvadoriana Hustedt, 1952
- Species Nitzschia sancti-francisci A. Witkowski & Lange-Bertalot in Witkowski et al., 2015
- Species Nitzschia sansimoni S.Blanco, I.Alvarez-Blanco & C.Cejudo-Figueiras, 2012
- Species Nitzschia sansomei Foged, 1966
- Species Nitzschia scabra Cleve, 1883
- Species Nitzschia scalaris (Ehrenberg) W.Smith, 1853 accepted as Tryblionella scalaris (Ehrenberg) P.Siver & P.B.Hamilton, 2005
- Species Nitzschia scaligera Grunow, 1880
- Species Nitzschia scalpelliformis Grunow, 1880
- Species Nitzschia schauinslandi Hustedt in Schmidt et al., 1922
- Species Nitzschia schefterae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia scherffeliana Krenner, 1926
- Species Nitzschia scheschukowae
- Species Nitzschia schiellerupii Foged, 1966
- Species Nitzschia schliephackeana Grunow ex Rabenhorst, 1864
- Species Nitzschia schoenfeldii (Hustedt) F.W.Mills, 1934 accepted as Navicula schoenfeldii f. schoenfeldii Hustedt, 1930
- Species Nitzschia schwabei Krasske ex Lange-Bertalot in Lange-Bertalot, Kulbs, Lauser, Norpel-Schempp & Willmann, 1996
- Species Nitzschia schweikertii Witkowski, Lange-Bertalot, Ruppel & Kociolek, 2004
- Species Nitzschia schweinfurthii Grunow in Van Heurck, 1881
- Species Nitzschia schweinfurthii Grunow in Rabenhorst, 1864
- Species Nitzschia scoliotropis Cleve, 1900
- Species Nitzschia scutellum (W.Smith) Wolle, 1890 accepted as Tryblionella scutellum W.Smith, 1853
- Species Nitzschia secallii Azpeitia y Moros, 1911
- Species Nitzschia seiboldia Schrader, 1974
- Species Nitzschia sellingii Berg, 1953
- Species Nitzschia semicostata Boyer, 1920
- Species Nitzschia semidesum Hohn & Hellerman, 1963
- Species Nitzschia semigibbosa Van Heurck, 1909
- Species Nitzschia semirobusta Lange-Bertalot, 1993
- Species Nitzschia senegalensis Grunow, 1880
- Species Nitzschia senegalensis Grunow, 1880
- Species Nitzschia sentiformis Hohn & Hellerman, 1963
- Species Nitzschia separanda (Hustedt) Hasle, 1972 accepted as Fragilariopsis separanda Hustedt, 1958
- Species Nitzschia seratia Cleve accepted as Nitzschia seriata Cleve, 1883
- Species Nitzschia serians Cleve & Grunow, 1880
- Species Nitzschia seriata Cleve, 1883 accepted as Pseudo-nitzschia seriata (Cleve) H.Peragallo, 1899
- Species Nitzschia serpenticula Cholnoky, 1968
- Species Nitzschia serpentiformis Carter, 1966
- Species Nitzschia serpentiraphe Lange-Bertalot, 1993
- Species Nitzschia serrata Manguin, 1952
- Species Nitzschia shanxiensis Q.Liu & S.L.Xie in Liu et al., 2017
- Species Nitzschia sheshukowae Skvortzow, 1971
- Species Nitzschia siberica Grunow in Cleve & Grunow, 1880
- Species Nitzschia sibirica Skvortzow, 1938
- Species Nitzschia sibirica Kozlowsky, 1890
- Species Nitzschia sibula M.H.Giffen, 1973
- Species Nitzschia sicula (Castracane) Hustedt
- Species Nitzschia sieboldia H.J. Schrader, 1974
- Species Nitzschia sierraleonensis Woodhead & Tweed, 1960
- Species Nitzschia sigma (Kützing) W.Smith, 1853
- Species Nitzschia sigmaformis Hustedt
- Species Nitzschia sigmatella Gregory, 1854 accepted as Stenopterobia sigmatella (Gregory) R. Ross in Hartley, 1986
- Species Nitzschia sigmatoformis
- Species Nitzschia sigmoidea (Nitzsch) W.Smith, 1853
- Species Nitzschia sigmoidea Østrup, 1910
- Species Nitzschia silica Archibald, 1966
- Species Nitzschia silicula Hustedt, 1955
- Species Nitzschia siliqua Archibald, 1966
- Species Nitzschia similis Hustedt, 1937
- Species Nitzschia similis Cleve-Euler, 1917
- Species Nitzschia simplex Hustedt, 1956
- Species Nitzschia simpliciformis Cholnoky, 1963
- Species Nitzschia simsiae Witkowski, Lange-Bertalot & Kociolek in Witkowski et al., 2015
- Species Nitzschia sinensis Liu et al., 1984
- Species Nitzschia singalensis Spitta, 1920
- Species Nitzschia sinuata (Thwaites) Grunow, 1880 accepted as Grunowia sinuata (Thwaites) Rabenhorst, 1864
- Species Nitzschia skabitschewskii (Skvortzov & Zabelina, 2012)
- Species Nitzschia skabitschewskyi Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia skowronekii Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia slesvicensis Grunow
- Species Nitzschia smithii Ralfs, 1861
- Species Nitzschia sociabilis Hustedt, 1957
- Species Nitzschia socialis Gregory, 1857
- Species Nitzschia solea Jurilj, 1957
- Species Nitzschia solea Hustedt in Schmidt et al., 1922
- Species Nitzschia solgensis Cleve-Euler, 1952
- Species Nitzschia solida J.Frenguelli & H.A.Orlando, 1958
- Species Nitzschia solita Hustedt, 1953
- Species Nitzschia sonora Carter, 1966
- Species Nitzschia soratensis E.A.Morales & M.L.Vis, 2007
- Species Nitzschia sovereignii VanLandingham, 1978
- Species Nitzschia spathulata W.Smith, 1853
- Species Nitzschia spathulatoides Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia spathulifera Grunow in Cleve & Grunow, 1880
- Species Nitzschia speciosa Hustedt, 1945
- Species Nitzschia spectabilis (Ehrenberg) Ralfs, 1861
- Species Nitzschia spectabilis W. Smith, 1853
- Species Nitzschia spelaea Krieger, 1944
- Species Nitzschia sphaerophora A.Cleve
- Species Nitzschia spiculoides Hustedt, 1949
- Species Nitzschia spiculum Hustedt, 1949
- Species Nitzschia spinarum Lange-Bertalot in Lange-Bertalot & Metzeltin, 1996
- Species Nitzschia spinifera Z.Levkov, D.Metzeltin & S.Krstic, 2006
- Species Nitzschia spiralis (Kützing) De Toni, 1892 accepted as Ceratoneis spiralis Kützing, 1844
- Species Nitzschia spiralis Mereschkowsky, 1901
- Species Nitzschia spirilliformis Kufferath, 1956
- Species Nitzschia stagnorum Rabenhorst, 1860 accepted as Nitzschia umbonata (Ehrenberg) Lange-Bertalot, 1978
- Species Nitzschia staurophora Giffen, 1967
- Species Nitzschia steenbergensis Giffen, 1973
- Species Nitzschia stefaninii Frenguelli, 1929
- Species Nitzschia stellata Manguin, 1957
- Species Nitzschia stelmachpessiana Hamsher et al., 2016
- Species Nitzschia steynii Cholnoky, 1966
- Species Nitzschia stiliformis Hustedt in Schmidt et al., 1922
- Species Nitzschia stimulus Cholnoky, 1961
- Species Nitzschia stockmayeri Pantocsek, 1902
- Species Nitzschia stoliczkiana Grunow
- Species Nitzschia stompsii Cholnoky, 1963
- Species Nitzschia strelnikovae Lange-Bertalot, 2005
- Species Nitzschia stricta Hustedt, 1949
- Species Nitzschia strigillata Hustedt, 1937
- Species Nitzschia striolata Hustedt, 1938
- Species Nitzschia stubstagnorum Skvortzov, 2012
- Species Nitzschia subaccommodata H.P. Gandhi, 1998 accepted as Nitzschia subaccommodata H.P.Gandhi ex Karthick, 2020
- Species Nitzschia subaccommodata H.P.Gandhi ex Karthick, 2020
- Species Nitzschia subacicularis Hustedt, 1922
- Species Nitzschia subacuta Hustedt, 1922
- Species Nitzschia subadapta Cholnoky, 1958
- Species Nitzschia subamphioxoides Hustedt, 1959
- Species Nitzschia subandina (Frenguelli) Kociolek & Vouilloud, 2020
- Species Nitzschia subapiculata H.P. Gandhi, 1998 accepted as Nitzschia subapiculata H.P.Gandhi ex Karthick, 2020
- Species Nitzschia subapiculata H.P.Gandhi ex Karthick, 2020
- Species Nitzschia subbacata Manguin ex Kociolek & Reviers, 1996
- Species Nitzschia subcapitata Østrup, 1910
- Species Nitzschia subcapitellata Hustedt, 1939
- Species Nitzschia subcohaerens (Grunow.) Van Heurck, 1896 accepted as Homoeocladia subcohaerens var. subcohaerens Grunow, 1878
- Species Nitzschia subcommunis Hustedt, 1949
- Species Nitzschia subconfinis Cholnoky, 1968
- Species Nitzschia subconstricta Desikachary & Prema, 1987
- Species Nitzschia subconstricta Grunow in mss. Lange-Bertalot & Krammer, 1987
- Species Nitzschia subcostata Grunow in Cleve & Grunow, 1880
- Species Nitzschia subcurvata G.R.Hasle, 1964
- Species Nitzschia subdenticula Hustedt, 1942
- Species Nitzschia subdilatata Grunow in Cleve & Grunow, 1880
- Species Nitzschia subfalcata T.Marsson, 1900
- Species Nitzschia subfradulenta G.R. Hasle, 1974
- Species Nitzschia subfraudulenta G.R.Hasle, 1974
- Species Nitzschia subfrequens R. Simonsen, 1960
- Species Nitzschia subfrustulum Hustedt, 1939
- Species Nitzschia subgraciloides H.P. Gandhi, 1998
- Species Nitzschia subhybrida Hustedt in Schmidt et al., 1922
- Species Nitzschia subinflata Hustedt, 1922
- Species Nitzschia subingenua Guermeur, 1954
- Species Nitzschia subinvicta Hustedt, 1950
- Species Nitzschia subinvisitata Guermeur, 1954
- Species Nitzschia sub-kutzingiana Skvortzov, 2012
- Species Nitzschia sublaevis H.P. Gandhi, 1998 accepted as Nitzschia sublaevis H.P.Gandhi ex Karthick, 2020
- Species Nitzschia sublaevis H.P.Gandhi ex Karthick, 2020
- Species Nitzschia sublanceolata Archibald, 1982
- Species Nitzschia sublica H.P. Gandhi, 1998 accepted as Nitzschia sublica H.P.Gandhi ex Karthick, 2020
- Species Nitzschia sublica H.P.Gandhi ex Karthick, 2020
- Species Nitzschia sublinearis Hustedt, 1930
- Species Nitzschia sublineata Hasle, 1972
- Species Nitzschia sublongirostris H.P. Gandhi, 1998 accepted as Nitzschia sublongirostris H.P.Gandhi ex Karthick, 2020
- Species Nitzschia sublongirostris H.P.Gandhi ex Karthick, 2020
- Species Nitzschia submarina Hustedt in Schmidt et al., 1921
- Species Nitzschia submediocris Hustedt, 1956
- Species Nitzschia subodiosa Cholnoky, 1960
- Species Nitzschia subpacifica Hasle, 1965
- Species Nitzschia subpalea Skvortzow, 1971
- Species Nitzschia subpalea Skvortzov, 1975
- Species Nitzschia subpunctata Cholnoky, 1960
- Species Nitzschia subrecta Grunow, 1878
- Species Nitzschia subregula Hustedt in Schmidt et al., 1924
- Species Nitzschia subromana Hustedt, 1954
- Species Nitzschia subrostrata Hustedt, 1942
- Species Nitzschia subrostratoides Cholnoky, 1966
- Species Nitzschia subsalsa Cholnoky, 1968
- Species Nitzschia subtibetica Skvortzow, 1971
- Species Nitzschia subtilioides Hustedt, 1959
- Species Nitzschia subtilis (Kützing) Grunow, 1880 accepted as Nitzschia linearis var. subtilis (Grunow) Hustedt, 1923
- Species Nitzschia subtropica Guermeur, 1954
- Species Nitzschia subtubicola H.Germain, 1981
- Species Nitzschia subulata (Brebisson in Kutzing) De Toni, 1892 accepted as Ceratoneis subulata Brébisson in Kutzing, 1846
- Species Nitzschia subvitrea Hustedt accepted as Nitzschia vitrea var. subvitrea (Hustedt) E.J.F.Wood, 1961
- Species Nitzschia suchlandti Hustedt, 1943
- Species Nitzschia suecica (Grunow in Cleve & Grunow) Cleve-Euler, 1932 accepted as Nitzschia linearis var. suecica Grunow, 1880
- Species Nitzschia suikoensis Koizumi, 1980
- Species Nitzschia sulcata Grunow, 1880
- Species Nitzschia sundaensis Hustedt, 1937
- Species Nitzschia sungariensis (Skvortzov, 2012)
- Species Nitzschia superba Leuduger-Fortmorel, 1879
- Species Nitzschia supralitorea Lange-Bertalot, 1979
- Species Nitzschia surirelloidea Prowse, 1962
- Species Nitzschia svedstrupii Foged, 1966
- Species Nitzschia syrachii Foged, 1966
- Species Nitzschia szaboi Pantocsek, 1889
- Species Nitzschia tabellaria (Grunow) Grunow, 1880 accepted as Denticula tabellaria Grunow, 1862
- Species Nitzschia tabellaria Schiedler, 1913
- Species Nitzschia taenia W.Smith, 1853
- Species Nitzschia taenia Hustedt, 1958
- Species Nitzschia taeniiformis Simonsen, 1987
- Species Nitzschia tainensis Foged, 1966
- Species Nitzschia tallyana Grunow, 1882
- Species Nitzschia tamnaeana Guermeur, 1954
- Species Nitzschia tantata Carter & Denny, 1992
- Species Nitzschia tarda Hustedt, 1949
- Species Nitzschia taygeteae Lobban, Ashworth, Calaor & E.C.Ther. in Lobban et al., 2019
- Species Nitzschia taylorii B.Alakananda, P.B.Hamilton & B.Karthick, 2012
- Species Nitzschia tehermalis
- Species Nitzschia teletzkensis Sheshukova in Poretzky & Sheshukova, 1953
- Species Nitzschia telezkoensis Sheshukova (Scheschukova) in Proschkina-Lavrenko, 1950
- Species Nitzschia tenellum Brébisson
- Species Nitzschia tenera Meister, 1937
- Species Nitzschia tenerifa Lange-Bertalot, 1987
- Species Nitzschia tenuiarcuata Takano, 1983
- Species Nitzschia tenuirostris Mer.
- Species Nitzschia tenuirostris Manguin in Bourrelly & Manguin, 1952
- Species Nitzschia tenuis W.Smith, 1853
- Species Nitzschia tenuis Eulenstein, 1868
- Species Nitzschia tenuissima H.Peragallo & M.Peragallo, 1900
- Species Nitzschia tenuistriata Hustedt in Schmidt et al., 1922
- Species Nitzschia tergestina (Kützing) Ralfs, 1861 accepted as Synedra tergestina Kützing, 1844
- Species Nitzschia terrestris (J.B.Petersen) Hustedt, 1934 accepted as Nitzschia vermicularis var. terrestris J.B.Petersen, 1928
- Species Nitzschia terricola Lund, 1946
- Species Nitzschia terryana Tempère & M. Peragallo in Tempère & Peragallo, 1914
- Species Nitzschia tetraplacata Mereschkowsky, 1902-1903
- Species Nitzschia thalliana De Toni, 1892
- Species Nitzschia thermalis (Ehrenberg) Auerswald, 1861
- Species Nitzschia thermaloides Hustedt, 1955
- Species Nitzschia thienemanni Hustedt, 1938
- Species Nitzschia tibetana Hustedt, 1922
- Species Nitzschia tiltilensis Frenguelli, 1949 †
- Species Nitzschia tingrica Jao & Y.Y. Lee in Jao, Zhu & Y.Y. Lee, 1974
- Species Nitzschia tingrica Jao & Lee in Jao, Zhu & Lee, 1974
- Species Nitzschia tirstrupensis Foged, 1963
- Species Nitzschia tongatensis Grunow in Cleve & Grunow, 1880
- Species Nitzschia tonkinensis Amossé, 1969
- Species Nitzschia tonoensis Foged, 1966
- Species Nitzschia torta H.P.Gandhi, 1961
- Species Nitzschia toskalensis P.B. Hamilton & J. Weckström, 2006
- Species Nitzschia towutensis Hustedt, 1942
- Species Nitzschia traheaformis Ch.Li, Witkowski & Sh.Yu in Witkowski et al., 2016
- Species Nitzschia translucida Hustedt, 1959
- Species Nitzschia transtagensis E.Morales, Novais, C.E.Wetzel, Morais & Ector
- Species Nitzschia transvaalensis Cholnoky, 1958
- Species Nitzschia transylvanica Pantocsek, 1892
- Species Nitzschia triconfusa VanLandingham, 1978
- Species Nitzschia tripudio Alakananda, B.Karthick, J.C.Taylor & P.B.Hamilton, 2015
- Species Nitzschia trobajoae A.Witkowski, Lange-Bertalot & Kociolek in Witkowski et al., 2015
- Species Nitzschia tropica Hustedt, 1949
- Species Nitzschia tryblionella Hantzsch, 1860
- Species Nitzschia tubicola Grunow, 1880
- Species Nitzschia tumida Hantzsch, 1861
- Species Nitzschia tumulana Patrick & Freese, 1961
- Species Nitzschia tungtingiana Skvortzov, 2012
- Species Nitzschia turgidula Hustedt, 1958
- Species Nitzschia turgiduloides G.R.Hasle, 1965
- Species Nitzschia turkestanica Kisselev, 1939
- Species Nitzschia uberifibulata Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia ultima Simonsen, 1992
- Species Nitzschia umaoiensis Akiba, 1985
- Species Nitzschia umbilicata Hustedt, 1949
- Species Nitzschia umbonata (Ehrenberg) Lange-Bertalot, 1978 accepted as Navicula umbonata Ehrenberg, 1837
- Species Nitzschia ungeri (Grunow) Schütt, 1896
- Species Nitzschia ushkaniensis Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia vacillata Giffen, 1967
- Species Nitzschia vacua Hustedt, 1950
- Species Nitzschia valdecostata Lange-Bertalot & Simonsen, 1978
- Species Nitzschia valdestriata Aleem & Hustedt, 1951
- Species Nitzschia valens (Ehrenberg) Ralfs, 1861 accepted as Synedra valens Ehrenberg, 1843
- Species Nitzschia valga Cholnoky, 1968
- Species Nitzschia valida Cleve & Grunow, 1878
- Species Nitzschia validissima Cholnoky, 1962
- Species Nitzschia vana Cholnoky, 1963
- Species Nitzschia vancauwenberghiana Hamsher et al., 2016
- Species Nitzschia vandeputteana Hamsher et al., 2016
- Species Nitzschia vandermerwei Cholnoky, 1957
- Species Nitzschia vanheurckii (Peragallo) Hasle, 1972 accepted as Fragilaria vanheurckii Peragallo, 1921
- Species Nitzschia vanhoeffenii Heiden & Kolbe, 1928
- Species Nitzschia vanoyei Cholnoky, 1954
- Species Nitzschia variepunctata Heiden, 1900
- Species Nitzschia vasnaii H.P.Gandhi, 1960
- Species Nitzschia vasta Hustedt, 1939
- Species Nitzschia vedelii Foged, 1966
- Species Nitzschia velazqueziana Hamsher et al., 2016
- Species Nitzschia veneziana Cholnoky in Lange-Bertalot & Krammer, 1987
- Species Nitzschia ventricosa Kitton, 1873
- Species Nitzschia vermica Skvortzow, 1935
- Species Nitzschia vermica Skvortzow, 1935
- Species Nitzschia vermicularis (Kützing) Hantzsch, 1860 accepted as Frustulia vermicularis Kützing, 1833
- Species Nitzschia vermicularoides Lange-Bertalot
- Species Nitzschia vermiculata Castracane, 1886
- Species Nitzschia verrucosa O'Meara, 1869
- Species Nitzschia vexans Grunow in Van Heurck, 1881
- Species Nitzschia victoriae (Grunow) Cleve, 1898 accepted as Tryblionella victoriae Grunow, 1862
- Species Nitzschia vidarbhensis Sarode & Kamat, 1984
- Species Nitzschia vidovichi sensu Hustedt in Schmidt et al., 1921
- Species Nitzschia vidovichii Grunow accepted as Homoeocladia vidovichii var. vidovichii Grunow, 1862
- Species Nitzschia vildaryana Rumrich & H. Lange-Bertalot in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia villarealii G. Fryxell, 2000
- Species Nitzschia virgata Roper, 1858 accepted as Hantzschia virgata (Roper) Grunow, 1880
- Species Nitzschia vishwanthae Singh, 1961
- Species Nitzschia visurgis Hustedt, 1957
- Species Nitzschia vitraea
- Species Nitzschia vitrea G.Norman, 1861
- Species Nitzschia vitrioides Frenguelli, 1923
- Species Nitzschia vivax W.Smith
- Species Nitzschia vivax Hantzsch, 1860
- Species Nitzschia vixfonticola Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia vixnegligenda H. Lange-Bertalot & G. Hoffmann in U. Rumrich, H. Lange-Bertalot & M. Rumrich, 2000
- Species Nitzschia vixpalea H.Lange-Bertalot & M.Werum, 2014
- Species Nitzschia voigtii Meister, 1937
- Species Nitzschia volcanica Sovereign, 1958
- Species Nitzschia voltaensis Foged, 1966
- Species Nitzschia volvendirostrata Ashworth, Dᶏbek & Witkowski in Witkowski et al., 2016
- Species Nitzschia vonhauseniae Cholnoky, 1954
- Species Nitzschia vulpecula Giffen, 1967
- Species Nitzschia vulpeculoides Giffen, 1973
- Species Nitzschia wallichiana Petit, 1888
- Species Nitzschia wangtzianii Skvortzov, 2012
- Species Nitzschia wankaremae Cleve, 1883
- Species Nitzschia wardhensis Sarode & Kamat, 1984
- Species Nitzschia weaveri Ciesielski, 1983
- Species Nitzschia weissflogii Grunow, 1878
- Species Nitzschia werumiana Kulikovskiy & Lange-Bertalot in Kulikovskiy et al., 2015
- Species Nitzschia westii Kellogg, Stuiver, et al., 1980
- Species Nitzschia widowichii Grunow, 1862
- Species Nitzschia williamsii B.Alakananda, P.B.Hamilton & B.Karthick, 2012
- Species Nitzschia wilmotteana Hamsher et al., 2016
- Species Nitzschia wipplingeri Cholnoky, 1966
- Species Nitzschia witkowskii Metzeltin & Lange-Bertalot, 1998
- Species Nitzschia wodensis J.R.Carter, 1964
- Species Nitzschia wolterecki Hustedt, 1942
- Species Nitzschia woltereckoides H.P. Gandhi, 1998 accepted as Nitzschia woltereckoides H.P.Gandhi ex Karthick, 2020
- Species Nitzschia woltereckoides H.P.Gandhi ex Karthick, 2020
- Species Nitzschia wuellerstorffii Lange-Bertalot in Lange-Bertalot & Krammer, 1987
- Species Nitzschia yalahau E. Novelo, R. Tavera & C. Ibarra, 2007
- Species Nitzschia yunchengensis Xie & Li, 1994
- Species Nitzschia zabelinae Skvortzow, 1971
- Species Nitzschia zabelini
- Species Nitzschia zahlbrucknerrii Pantocsek, 1912
- Species Nitzschia zebuana A.Mann, 1925
- Species Nitzschia zululandica Cholnoky, 1968
- Genus Nitzschiella L. Rabenhorst, 1864
- Genus Ophidocampa C.G. Ehrenberg, 1870
- Genus Perrya F. Kitton, 1874 †
- Genus Psammodictyon D.G. Mann in F.E. Round, R.M. Crawford & D.G. Mann, 1990 (3)
- Genus Pseudoeunotia accepted as Pseudo-eunotia A. Grunow in H. Van Heurck, 1881
- Genus Pseudo-nitschia accepted as Pseudo-nitzschia H. Peragallo in H. Peragallo & M. Peragallo, 1900
- Genus Pseudonitzschia accepted as Pseudo-nitzschia H. Peragallo in H. Peragallo & M. Peragallo, 1900 (1)
- Genus Pseudo-nitzschia H. Peragallo in H. Peragallo & M. Peragallo, 1900 (48)
- Genus Simonsenia H. Lange-Bertalot, 1979 (2)
- Genus Tryblionella W. Smith, 1853 (9)
- Family Bacillariales incertae sedis (5)
- Family Nitzschiaceae accepted as Bacillariaceae Ehrenberg, 1831
- Order Cymbellales (792)
- Order Dictyoneidales
- Order Lyrellales (15)
- Order Mastogloiales (88)
- Order Naviculales (2 077)
- Order Rhopalodiales (37)
- Order Surirellales (174)
- Order Thalassiophysales (105)
- Superorder Bacillariophycidae incertae sedis (32)
- Superorder Eunotiophycanae (293)
- Subclass Coscinodiscophycidae (877)
- Subclass Fragilariophycidae (483)
- Order Centrales
