Cheilanthes incisa, a small and rare endemic fern of Rio de Janeiro State (Brazil), was described in 1859. Hypolepis serrata, published ten years later, is usually considered a taxonomic synonym. Both names have typification problems, addressed here by designation of a neotype for C. incisa and selection of a lectotype of H. serrata from among Glaziou materials cited by Fée. Epidermal characteristics and spores of C. incisa are described for the first time and their diagnostic value assessed. Taxonomic relationships between C. incisa and putatively related cheilanthoid ferns are also discussed.