Achnanthes lanceolata var. ventricosa Hustedt, 1914 (original description)
Caloneis silicula var. tenuis Hustedt, 1915 (original description)
Eunotia robusta f. abrupta Hustedt, 1914 (original description)
Fragilaria virescens var. elliptica Hustedt, 1913 accepted as
Fragilariforma virescens var. elliptica (Hustedt) Kharitonov, 2005 (additional source)
Navicula bacilliformis var. cruciata Hustedt, 1914 (1915) (original description)
Navicula minima f. magis stauroneiformis (Grunow in Van Heurck) Hustedt, 1914 (new combination reference)
Neidium affine f. undulata Hustedt, 1914 (original description)
Neidium amphirhynchus var. constrictum Hustedt, 1914 (original description)
Neidium iridis f. maxima (Cleve) Hustedt, 1930 accepted as
Neidium affine f. maxima genuina O. Müller, 1898 (new combination reference)
Neidium productum var. constrictum Hustedt, 1914 (original description)
Pinnularia appendiculata var. naveana (Grunow) Hustedt, 1914 accepted as
Navicula naveana f. naveana Grunow, 1863 (new combination reference)
Pinnularia appendiculata var. silesiaca Hustedt, 1914 (original description)
Pinnularia borealis f. brevicostata Hustedt, 1914 (original description)
Pinnularia divergens var. undulata (M.Peragallo & Héribaud-Joseph) Hustedt, 1914 accepted as
Navicula divergens var. undulata M.Peragallo & Héribaud-Joseph, 1893 (new combination reference)
Pinnularia karelica var. stauroneiformis Hustedt in A. Schmidt, 1914 (original description)
Pinnularia major var. hyalina (Hustedt) Skabichevskii, 1942 (original description)
Pinnularia stauroptera var. mesogongyla (Ehrenberg) Hustedt, 1914 (new combination reference)
Pinnularia viridis var. interrupta Hustedt, 1914 (original description)
Surirella apiculata var. constricta Hustedt, 1914 (original description)