Achnanthes boyei Østrup, 1918 accepted as
Planothidium lanceolatum (Brébisson ex Kützing) Bukhtiyarova, 1999 (original description)
Achnanthes lanceolata var. subinflata Østrup, 1918 (original description)
Amphora dubiosa Østrup, 1918 (original description)
Caloneis fedderseni Østrup, 1918 (original description)
Caloneis islandica Østrup, 1918 (1920) (original description)
Caloneis jonssoni Østrup, 1918 (1920) (original description)
Caloneis procera f. procera Østrup, 1918 (1920) (original description)
Cyclotella minutissima (taxonomy source)
Cymbella dubia Østrup, 1920 (original description)
Cymbella islandica Østrup, 1920 (original description)
Cymbella jonssoni Østrup, 1918 (1920) (original description)
Cymbella linearis Østrup, 1918 (original description)
Cymbella marginata Østrup, 1918 (1920) (original description)
Cymbella recta Østrup, 1918 (1920) (original description)
Cymbella subconstricta Østrup, 1918 (1920) (original description)
Denticula islandica Østrup, 1918 (1920) (original description)
Diploneis ovalis f. subinflata Østrup, 1918 (original description)
Diploneis ovalis var. subinflata Østrup, 1918 (1920) (original description)
Eunotia islandica Østrup, 1918 (original description)
Fragilaria baculus Østrup, 1918 (1920) (original description)
Fragilaria mutabilis var. inflata Østrup, 1918 (original description)
Fragilaria rhombica Østrup, 1918 (1920) (original description)
Fragilaria triundulata E.V.Østrup (new combination reference)
Frustulia islandica Østrup, 1918 (1920) (original description)
Gomphonema irregulare Østrup, 1918 (1920) (original description)
Gomphonema islandicum Østrup, 1918 (1920) (original description)
Gomphonema medioconstrictum Østrup, 1918 (1920) (original description)
Hantzschia amphioxys f. abnormis Østrup, 1920 (original description)
Hantzschia truncata Østrup, 1918 (1920) (original description)
Melosira steffanssoni Østrup, 1918 (1920) (original description)
Meridion circulare f. anormalis Østrup, 1918 (1920) (original description)
Navicula angustefasciata Østrup, 1920 (original description)
Navicula bacillum var. densestriata Østrup, 1920 (original description)
Navicula boyei Østrup, 1920 (original description)
Navicula curtestriata Østrup, 1918 (original description)
Navicula dicephala f. undulata Østrup, 1918 (1920) (original description)
Navicula exilior Østrup, 1918 (1920) (original description)
Navicula fustis Østrup, 1918 (1920) (original description)
Navicula islandica Østrup, 1918 (original description)
Navicula jonssoni Østrup, 1918 (original description)
Navicula lyrigera Østrup, 1918 (original description)
Navicula ostenfeldii f. ostenfeldii Østrup, 1918 (original description)
Navicula pinnularioides f. pinnularioides Østrup, 1920 (original description)
Navicula semifasciata Østrup, 1918 (original description)
Navicula spatiata Østrup, 1918 (original description)
Navicula thingvallae Østrup, 1918 † (original description)
Neidium incurvum (Gregory) Østrup, 1918 (new combination reference)
Neidium incurvum var. incurvum (Gregory) Østrup, 1918 (new combination reference)
Neidium islandicum Østrup, 1918 (original description)
Neidium lineare Østrup, 1918 (original description)
Neidium panduriforme Østrup, 1918 (original description)
Nitzschia glaberrima Østrup, 1918 (original description)
Nitzschia jonssoni Østrup, 1918 (original description)
Nitzschia mucronata Østrup, 1918 (original description)
Pinnularia alpina var. linearis Østrup, 1918 (original description)
Pinnularia borealis f. linearis (Heribaud) Østrup, 1918 accepted as
Navicula borealis var. linearis Héribaud, 1908 (new combination reference)
Pinnularia brandelii var. linearis Østrup, 1918 † (original description)
Pinnularia brevicostata var. islandica Østrup, 1918 (original description)
Pinnularia bryophila Østrup, 1918 (original description)
Pinnularia densestriata Østrup, 1918 (original description)
Pinnularia gigantea Østrup, 1918 (original description)
Pinnularia islandica var. islandica Østrup, 1918 (1920) (original description)
Pinnularia karelica var. rostrata Østrup, 1918 (1920) (original description)
Pinnularia leptosoma var. undulata Østrup, 1918 (1920) (original description)
Pinnularia parva var. minuta Østrup, 1918 (original description)
Pinnularia perexilis Østrup, 1918 (1920) (original description)
Pinnularia subundulata E.V.Østrup, 1918 (original description)
Pinnularia thoroddseni Østrup, 1918 (1920) (original description)
Stauroneis anceps var. elliptica Østrup, 1918 (1920) (original description)
Stauroneis bifissa Østrup, 1918 (1920) (original description)
Stauroneis elegantula var. elegantula Østrup, 1918 (1920) (original description)
Stauroneis parvula var. capitata Østrup, 1918 (original description)
Stauroneis perexilis Østrup, 1918 (1920) (original description)
Stauroneis stefanssoni Østrup, 1918 (1920) (original description)
Surirella asymmetrica var. asymmetrica Østrup, 1918 (1920) (original description)
Surirella granulata var. elliptica Østrup, 1918 (1920) (original description)
Surirella islandica var. islandica Østrup, 1918 (1920) (original description)
Surirella jonssoni var. jonssoni Østrup, 1918 (1920) (original description)
Synedra rumpens var. islandica Østrup, 1918 (1920) (original description)
Synedra ulna f. arcuata Østrup, 1918 (1920) (original description)