Achnanthes lanceolata f. rostrata (Oestrup) Hustedt, 1957 accepted as Achnanthes rostrata Oestrup, 1902 (new combination reference)
Actinocyclus normanii f. normanii (W. Gregory) Hustedt, 1957 accepted as Coscinodiscus normanii Gregory ex Greville, 1859 (new combination reference)
Actinocyclus normanii f. subsalsa (Juhlin-Dannfelt) Hustedt, 1957 accepted as Coscinodiscus subsalsus Juhlin-Dannfelt, 1882 (new combination reference)
Caloneis amphisbaena f. subsalina (Donkin) van der Werff & Huls, 1957 accepted as Navicula subsalina f. subsalina Donkin, 1870 (new combination reference)
Caloneis bacillum f. lancettula (Schulz) Hustedt, 1957 accepted as Caloneis aemula var. lancettula Schultz, 1926 (new combination reference)
Cocconeis placentula f. euglypta (Ehrenberg) Hustedt, 1957 accepted as Cocconeis euglypta Ehrenberg, 1854 (new combination reference)
Cocconeis placentula f. lineata (Ehrenberg) Hustedt, 1957 accepted as Cocconeis lineata Ehrenberg, 1843 (new combination reference)
Cyclotella nana Hustedt, 1957 (original description)
Cymatopleura elliptica f. nobilis (Hantzsch) Hustedt, 1957 (new combination reference)
Cymatopleura solea f. regula (Ehrenberg) Hustedt, 1957 accepted as Surirella regula Ehrenberg, 1843 (new combination reference)
Diatoma vulgare f. linearis (Grunow in Van Heurck) Hustedt, 1957 accepted as Diatoma vulgare var. linearis Grunow in Van Heurck, 1881 accepted as Diatoma vulgaris var. linearis Grunow, 1881 (new combination reference)
Epithemia turgida f. granulata (Ehrenberg) Hustedt, 1957 accepted as Eunotia granulata Ehrenberg, 1836 (new combination reference)
Epithemia zebra f. porcellus (Kützing) van der Werff & Huls, 1957 accepted as Epithemia porcellus Kützing, 1844 (new combination reference)
Epithemia zebra f. saxonica (Kützing) Hustedt, 1957 accepted as Epithemia saxonica Kützing, 1844 (new combination reference)
Eunotia arcus f. bidens (Grunow) Hustedt, 1957 accepted as Eunotia arcus var. bidens Grunow, 1881 (new combination reference)
Eunotia lunaris f. subarcuata (C.W.Nägeli) J.Frenguelli, 1933 accepted as Synedra subarcuata Naegeli ex Kützing, 1849 (new combination reference)
Eunotia pectinalis f. undulata (J.Ralfs) A.Berg, 1939 accepted as Fragilaria pectinalis var. undulata Ralfs, 1843 (new combination reference)
Eunotia pectinalis f. ventralis (Ehrenberg) Hustedt, 1957 accepted as Eunotia ventralis Ehrenberg, 1843 (new combination reference)
Fragilaria capucina f. lanceolata (Grunow) Skabichevskii, 1960 accepted as Fragilaria capucina var. lanceolata Grunow, 1881 (new combination reference)
Fragilaria capucina f. mesolepta (Rabenhorst) Hustedt, 1957 accepted as Fragilaria capucina var. mesolepta auct. non Hustedt (new combination reference)
Fragilaria construens f. binodis (Ehrenberg) Hustedt, 1957 accepted as Navicula binodis Ehrenberg, 1840 accepted as Neidiomorpha binodis (Ehrenberg) M.Cantonati, Lange-Bertalot & N.Angeli, 2010 (new combination reference)
Fragilaria construens f. subsalina (Hustedt) Hustedt, 1957 (new combination reference)
Fragilaria construens f. triundulata (Reichelt ex Hartz & Ostrup) Hustedt, 1957 accepted as Fragilaria construens var. triundulata Riechelt, 1899 (new combination reference)
Fragilaria construens f. venter (Ehrenberg) Hustedt, 1957 accepted as Fragilaria venter var. venter Ehrenberg, 1854 (new combination reference)
Fragilaria familaris (Kützing) Hustedt, 1957 (new combination reference)
Fragilaria pinnata f. lancettula (Schumann) Hustedt, 1957 accepted as Fragilaria lancettula Schumann, 1867 (new combination reference)
Frustulia creuzburgensis (Krasske) Hustedt, 1957 accepted as Navicula creuzburgensis var. creuzburgensis Krasske, 1927 (new combination reference)
Gomphonema angustatum f. sarcophagus (Gregory) Hustedt, 1957 accepted as Gomphonema sarcophagus f. sarcophagus Gregory, 1856 (new combination reference)
Gomphonema constrictum f. capitata (Ehrenberg) Hustedt, 1957 accepted as Gomphonema capitatum f. capitatum Ehrenberg, 1838 (new combination reference)
Navicula bremensis Hustedt, 1957 (original description)
Navicula constans var. symmetrica Hustedt, 1957 accepted as Placoneis symmetrica (Hustedt) H. Lange-Bertalot in D. Metzeltin, H. Lange-Bertalot & F. García-Rodríguez, 2005 (original description)
Navicula crucicula f. rostrata (Tarnavschi) Hustedt, 1957 accepted as Navicula crucicula var. rostrata Tarnavschi & Mitroiu, 1940 (new combination reference)
Navicula cryptocephala f. veneta (Kützing) Hustedt, 1957 accepted as Navicula veneta var. veneta Kützing, 1844 (new combination reference)
Navicula difficillimoides Hustedt, 1957 (original description)
Navicula digna Hustedt, 1957 (original description)
Navicula fluviatilis Hustedt, 1957 (original description)
Navicula fossaloides Hustedt, 1957 (original description)
Navicula frugalis Hustedt, 1957 (original description)
Navicula hungarica f. capitata (Ehrenberg) Hustedt, 1957 accepted as Navicula capitata var. capitata Ehrenberg, 1838 (new combination reference)
Navicula ingenua Hustedt, 1957 (original description)
Navicula insociabilis var. dissipatoides Hustedt, 1957 accepted as Fallacia dissipatoides (Hustedt) D. Metzeltin, H. Lange-Bertalot & F. García-Rodríguez, 2005 (original description)
Navicula lesmonensis Hustedt, 1957 (original description)
Navicula mutica f. nivalis (Ehrenberg) van der Werff & Huls, 1960 accepted as Navicula nivalis var. nivalis Ehrenberg, 1853 (new combination reference)
Navicula oblonga f. subcapitata (Pantocsek) Hustedt, 1957 accepted as Navicula oblonga var. subcapitata Pantocsek, 1902 (new combination reference)
Navicula paludosa Hustedt, 1957 (original description)
Navicula peratomus Hustedt, 1957 (original description)
Navicula protracta f. elliptica Hustedt, 1957 (original description)
Navicula protractoides Hustedt, 1957 (original description)
Navicula pupula f. capitata (Skvortzow & Meyer) Hustedt, 1961 accepted as Navicula pupula var. capitata Hustedt, 1934 (new combination reference)
Navicula pupula f. rostrata (Hustedt) Hustedt, 1961 accepted as Navicula pupula var. rostrata Hustedt, 1911 (new combination reference)
Navicula ventosa Hustedt, 1957 (original description)
Neidium affine f. constricta (Frenguelli) Hustedt, 1957 (new combination reference)
Nitzschia adamata Hustedt, 1957 (original description)
Nitzschia admissa Hustedt, 1957 (original description)
Nitzschia agnita Hustedt, 1957 (original description)
Nitzschia amplectens Hustedt, 1957 (original description)
Nitzschia frequens Hustedt, 1957 (original description)
Nitzschia fruticosa Hustedt, 1957 (original description)
Nitzschia hungarica f. linearis (Grunow in Cleve & Grunow) Hustedt, 1957 accepted as Nitzschia hungarica f. linearis Grunow in Cleve & Grunow, 1880 (new combination reference)
Nitzschia manca Hustedt, 1957 (original description)
Nitzschia punctata f. coarctata (Grunow in Cleve & Moller; Grunow in Cleve & Grunow) Hustedt, 1957 accepted as Nitzschia coarctata var. coarctata Grunow in Cleve & Möller, 1878 (new combination reference)
Nitzschia sociabilis Hustedt, 1957 (original description)
Nitzschia thermalis f. intermedia (Grunow in Van Heurck) Hustedt, 1957 accepted as Nitzschia thermalis var. intermedia Grunow in Van Heurck, 1881 (new combination reference)
Nitzschia visurgis Hustedt, 1957 (original description)
Pinnularia gibba f. linearis (Hustedt) Hustedt, 1957 accepted as Pinnularia gibba var. linearis Hustedt, 1930 (new combination reference)
Pinnularia mesolepta f. vix undulata Hustedt, 1957 (original description)
Pinnularia microstauron f. diminuta (Grunow) Hustedt, 1930 accepted as Navicula brebissonii var. diminuta Grunow, 1880 (original description)
Pinnularia microstauron f. linearis (Otto Müller) Hustedt, 1930 accepted as Pinnularia brebissonii f. linearis Otto Müller, 1898 (original description)
Rhaphoneis surirella f. australis (Petit) Hustedt, 1957 (new combination reference)
Rhaphoneis surirella f. subsalina (Petit) Hustedt, 1957 accepted as Rhaphoneis fasciolata var. australis Petit, 1877 (new combination reference)
Rhopalodia gibba f. ventricosa (Kützing) Hustedt, 1957 accepted as Epithemia ventricosa Kützing, 1844 (new combination reference)
Stauroneis alabamae f. angulata (Heiden) Hustedt, 1957 (new combination reference)
Stauroneis borrichii f. subcapitata (J.B.Petersen) Lund accepted as Navicula borrichii var. subcapitata J.B.Petersen, 1915 (new combination reference)
Stauroneis nana Hustedt, 1957 (original description)
Stauroneis smithii f. incisa (Pantocsek) Hustedt, 1957 (new combination reference)
Surirella linearis f. constricta (Grunow) Hustedt, 1957 accepted as Surirella linearis f. constricta Grunow, 1862 (new combination reference)
Surirella nervosa (A.Schmidt) A.Mayer, 1913 accepted as Surirella tenera f. nervosa Schmidt in Schmidt et al., 1875 (new combination reference)
Surirella splendida f. punctata (Hustedt) Hustedt, 1957 (new combination reference)
Surirella tenera f. cristata Hustedt, 1957 (original description)
Surirella visurgis Hustedt, 1957 (original description)
Synedra acus f. radians (Kützing) Hustedt, 1957 accepted as Synedra radians var. radians Kützing, 1844 (new combination reference)
Synedra investiens f. rhomboidea Hustedt, 1957 (original description)
Synedra parasitica f. subconstricta (Grunow) Hustedt, 1957 accepted as Fragilaria parasitica var. subconstricta Grunow, 1881 (new combination reference)
Synedra pulchella f. lacerata (Hustedt) Hustedt, 1957 accepted as Synedra pulchella var. lacerata Hustedt, 1926 accepted as Fragilaria pulchella var. lacerata (Hustedt) Kharitonov, 2005 (new combination reference)
Synedra pulchella f. naviculacea (Grunow in Van Heurck) Hustedt, 1957 accepted as Synedra pulchella var. naviculacea Grunow in Van Heurck, 1881 (new combination reference)
Synedra ulna f. biceps (Kützing) Hustedt, 1957 accepted as Synedra biceps f. biceps Kützing, 1844 (new combination reference)
Synedra ulna f. danica (Kützing) Hustedt, 1957 accepted as Synedra danica Kützing, 1844 (new combination reference)
Synedra ulna f. impressa (Hustedt in Schmidt et al.) Hustedt, 1957 accepted as Synedra ulna var. impressa Hustedt, 1921 (new combination reference)
Thalassiosira visurgis Hustedt, 1957 (original description)