Achnanthes affinis var. jamalinensis (Grunow in Cleve & Grunow) Cleve, 1895 accepted as
Achnanthes jamalinensis Grunow in Cleve & Grunow, 1880 (additional source)
Diatoma elongatum var. pachycephala (Grunow in Van Heurck) Hustedt, 1931 accepted as
Diatoma tenue var. pachycephala Grunow in Van Heurck, 1881 (new combination reference)
Dimeregramma marinum f. lanceolata (Peragallo & Peragallo) Hustedt, 1931 accepted as
Dimeregramma lanceolatum H.Peragallo & M.Peragallo, 1901 (new combination reference)
Fragilaria alpestris Krasske ex Hustedt, 1931 (original description)
Fragilaria atomus Hustedt, 1931 (original description)
Fragilaria constricta f. stricta (A.Cleve) Hustedt, 1931 (new combination reference)
Fragilaria constricta f. tetranodis Cleve-Euler, 1953 (new combination reference)
Fragilaria constricta f. trinodis Hustedt, 1931 accepted as
Fragilariforma constricta f. trinodis (Hustedt) Kharitonov, 2005 (original description)
Fragilaria inflata var. inflata (Heiden) Hustedt, 1931 accepted as
Synedra inflata Heiden, 1900 accepted as
Staurosira inflata (Heiden) A.Rusanov, Ács, E. Morales & Ector in Rusanov et al., 2018 (new combination reference)
Fragilaria inflata var. istvanffyi (Pantocsek) Hustedt, 1931 accepted as
Fragilaria istvanffyi var. istvanffyi Pantocsek, 1902 (new combination reference)
Fragilaria leptostauron f. dubia (Grunow) Hustedt, 1931 accepted as
Fragilaria harrisonii f. dubia Grunow, 1862 (new combination reference)
Fragilaria leptostauron f. leptostauron (Ehrenberg) Hustedt, 1931 accepted as
Biblarium leptostauron Ehrenberg, 1854 (new combination reference)
Fragilaria leptostauron var. rhomboides (Grunow) Hustedt, 1931 accepted as
Fragilaria harrisonii var. rhomboides Grunow, 1862 (new combination reference)
Fragilaria pinnata f. bullata (Østrup) Hustedt, 1931 accepted as
Fragilaria mutabilis var. bullata Østrup, 1910 (new combination reference)
Fragilaria pinnata f. capitata (Krieger) Hustedt, 1931 accepted as
Fragilaria pinnata var. capitata Krieger, 1929 (new combination reference)
Fragilaria pinnata f. intercedens (Grunow in Van Heurck) Hustedt, 1931 accepted as
Fragilaria mutabilis var. intercedens Grunow, 1881 (new combination reference)
Glyphodesmis williamsonii f. lanceolata (Peragallo & Peragallo) Hustedt, 1931 accepted as
Glyphodesmis lanceolata Peragallo & Peragallo, 1901 (new combination reference)
Grammatophora oceanica f. intermedia (Grunow) Hustedt, 1931 accepted as
Grammatophora oceanica var. intermedia Grunow, 1867 (new combination reference)
Grammatophora oceanica f. nodulosa (Grunow) Hustedt, 1931 accepted as
Grammatophora oceanica f. nodulosa Grunow, 1881 (new combination reference)
Grammatophora oceanica f. subtilissima (J.W. Bailey ex Ralfs in Pritchard) Hustedt, 1931 (new combination reference)
Grammatophora oceanica f. vulgaris (Grunow) Hustedt, 1931 accepted as
Grammatophora oceanica var. vulgaris Grunow, 1881 (new combination reference)
Licmophora abbreviata var. pappeana (Grunow) Hustedt, 1931 accepted as
Podosphenia pappeana Grunow, 1863 (new combination reference)
Licmophora ehrenbergii f. elegans (Mereschkowsky) Hustedt, 1931 accepted as
Licmophora elegans Mereschkowsky, 1901 (new combination reference)
Licmophora ehrenbergii f. grunowii (Mereschkowsky) Hustedt, 1931 accepted as
Licmophora grunowii var. grunowii Mereschkowsky, 1901 (new combination reference)
Licmophora juergensii f. chersonensis (Grunow in Van Heurck) Hustedt, 1931 accepted as
Licmophora juergensii var. chersonensis Grunow in Van Heurck, 1881 (new combination reference)
Licmophora juergensii f. elongata (Peragallo & Peragallo) Hustedt, 1931 accepted as
Licmophora juergensii var. elongata Peragallo & Peragallo, 1901 (new combination reference)
Licmophora paradoxa var. tincta (C.Agardh) Hustedt, 1931 accepted as
Gomphonema tinctum C.Agardh, 1831 (new combination reference)
Licmosphenia africana (Leuduger-Fortmorel) Hustedt, 1931 accepted as
Licmophora africana Leuduger-Fortmorel, 1898 (new combination reference)
Licmosphenia taylori Hustedt, 1931 accepted as
Licmophora taylori (Hustedt, 1931) Lobban & Ashworth, 2015 (original description)
Opephora gemmata f. gemmata (Grunow) Hustedt, 1931 accepted as
Sceptroneis gemmata Grunow, 1866 † (new combination reference)
Rhabdonema arcuatum var. robusta (Grunow) Hustedt, 1931 accepted as
Rhabdonema robustum Grunow, 1862 (new combination reference)
Rhabdonema arcuatum var. subrostratum (Fricke in Schmidt et al.) Hustedt, 1931 accepted as
Rhabdonema subrostratum var. subrostratum Fricke in Schmidt et al., 1899 (new combination reference)
Tetracyclus lacustris var. strumosa (Ehrenberg) Hustedt, 1931 accepted as
Biblarium strumosum Ehrenberg, 1854 (new combination reference)