Cymbella clericii Frenguelli, 1923 (original description)
Cymbella gastroides var. gigantea (Pantocsek) Frenguelli, 1923 † accepted as Cymbella gigantea Pantocsek, 1892 † (new combination reference)
Fragilaria pinnata var. intercedens (Grunow) Frenguelli, 1923 accepted as Fragilaria mutabilis var. intercedens Grunow, 1881 (new combination reference)
Navicula doello-juradoi Frenguelli, 1924 accepted as  (original description)
Navicula fasciata var. fontinalis (Grunow) Frenguelli, 1924 accepted as Navicula fontinalis Grunow, 1885 accepted as Caloneis fontinalis (Grunow) Cleve-Euler, 1932 (new combination reference)
Navicula peragalli Frenguelli, 1923 (original description)
Navicula peragalli var. gracilis Frenguelli, 1923 (original description)
Navicula peregrina var. perlonga Frenguelli, 1923 (original description)
Navicula silicula var. patagonica (Otto Müller) Frenguelli, 1923 accepted as Caloneis silicula f. patagonica Otto Müller, 1909 (new combination reference)
Navicula silicula var. ventricosa (Ehrenberg) Frenguelli, 1923 accepted as Navicula ventricosa var. ventricosa Ehrenberg, 1830 (new combination reference)
Navicula subcapitata var. hybrida (Grunow) Frenguelli, 1923 accepted as Navicula bicapitata var. hybrida Grunow, 1880 (new combination reference)
Navicula viridis var. patagonica Cleve, 1881 accepted as Caloneis patagonica (Cleve) Cleve, 1894 (additional source)
Nitzschia acicularis Frenguelli, 1923 (original description)
Stauroneis anceps var. abnormis Frenguelli, 1923 (1924) (original description)
Stauroneis anceps var. abnormis Frenguelli, 1923 (basis of record)
Surirella tuberosa var. costata Frenguelli, 1923 (original description)

Punta Arenas for Cymbella clericii Frenguelli, 1923 
Punta Arenas for Cymbella clericii Frenguelli, 1923 
Tierra del Fuego (Argentina) for Cymbella clericii Frenguelli, 1923 
Tierra del Fuego (Argentina) for Navicula cuspidata var. major Frenguelli, 1924 
Tierra del Fuego (Argentina) for Navicula cuspidata var. major Frenguelli, 1924