Abstract
A new monotypic genus, Pseudotrismegistia H. Akiy. & Tsubota, is proposed to accommodate P. undulata (Broth. & Yasuda) H. Akiy. & Tsubota. Pseudotrismegistia differs from the widely distributed genus Trismegistia in the weak differentiation of leaf shape between stems and branches, strong undulation in the upper portion of the leaf lamina, clearly differentiated forked costae of leaves, absence of well-marked borders at the leaf margins, and the alar cells arranged in a scalariform manner. The nearly equal size of alar cells that are scarcely inflated, as well as molecular analyses, suggests the genus should be assigned to the Heterophylliideae of the Sematophyllaceae.
