Actinoptychus minutus f. major Forti, 1913 (original description)
Cocconeis praecellens var. paucistriata Forti in Tempère & Peragallo, 1910, 1914 (original description)
Gephyria rinnboeckii (Pantocsek) Forti, 1912 (new combination reference)
Isthmia squinaboli var. crassior Forti, 1912 (original description)
Leudugeria epithemioides var. subarcuata Tempère, 1911 (original description)
Lithodesmium ehrenbergii f. dicentrica quadragona Forti, 1912 (original description)
Lithodesmium ehrenbergii f. ehrenbergii (Grunow in Van Heurck) Forti, 1912 accepted as
Triceratium ehrenbergii Grunow in Van Heurck, 1883 (new combination reference)
Lithodesmium ehrenbergii var. ehrenbergii Forti, 1912 (original description)
Melosira ornata var. reducta Forti, 1912 (original description)
Palmeria capillaris (J.Brown) Forti accepted as
Euodia capillaris Brun, 1891 (new combination reference)
Stephanopyxis lineata var. lineata (Ehrenberg) Forti, 1912 accepted as
Stephanodiscus lineatus Ehrenberg, 1854 (new combination reference)
Stephanopyxis polaris var. antiqua (Pantocsek) Forti, 1912 accepted as
Stephanopyxis antiqua Pantocsek, 1892 (new combination reference)
Stephanopyxis polaris var. polaris (Grunow) Forti, 1912 accepted as
Stephanopyxis turris var. polaris Grunow, 1884 accepted as
Eupyxidicula polaris (Grunow) S.Blanco & C.E.Wetzel, 2016 (new combination reference)
Stictodiscus parallelus f. minor Forti, 1912 (original description)
Stictodiscus parallelus var. trigona Forti, 1912 (original description)
Triceratium grande f. quadrata Forti, 1912 (original description)
Triceratium grande var. grande Forti, 1912 (original description)
Triceratium pantocsekii var. rectangularis Forti, 1912 (original description)
Triceratium radians var. italica Forti, 1912 (original description)
Triceratium subrotundatum sensu Forti, 1912 (original description)
Triceratium tridactylum var. saxolana Forti, 1912 (original description)
Triceratium trisulcum var. valida Forti, 1912 (original description)
Triceratium validum f. italica Forti, 1912 (original description)
Triceratium wittii f. quadrata Forti, 1912 (original description)
Xanthiopyxis acrolopha Forti, 1912 † (original description)