Phylogenetic relationships among the genera of the Ophioglossaceae sensu lato are controversial from the viewpoints of morphological and anatomical features. However, I demonstrated mainly from the spore morphological studies of the Ophioglossaceae on the Old World. I concluded that the Botrychiaceae (includes Botrychium and Helminthostachys) is composed of five genera, Botrychium (divided into 2 sections), Sceptridium (divided into 2 sections), Botrypus (divided into 2 sections), Japanobotryhium and Helminthostachys. Moreover, Ophioglossaceae sensu strict consists of two genera, Ophioglossum and Ophioderma. A key to the genus according to spore morphology is as follows; Spores subtriangular, or often rounded triangular in polar view, with almost projective basic ornamentations:Botrychiaceae. Spores tuberculate to verrucate, or often extervermiculate:Botrychium. Spores rugulo-reticulate with fine granules, or beset with irregularly fine projections:Sceptridium. Spores convolute or often uniting to form reticulate with finely striate:Japanobotrychium. Spores coarsely and largely verrucate with fine granules:Botrypus. Spores reticulum-like pattern, thin ridges decorated with delicate projections:Helminthostachys. Spores rounded triangular or globose in shape, with mostly depressed basic ornamentations:Ophioglossaceae. Spores usually globose, foveolate to foveo-reticulate, or often reticulum-like pattern:Ophioglossum. Spores large and rounded triangular in polar view, usually foveolate to reticulum-like pattern:Ophiodedrma.

Key words: Botrychiaceae, Ophioglossaceae, Ornamentation, spore morphology