The prothallial development of gametophytes of Olfersia alata and Olfersia cervina (Dryopteridaceae) is described and compared. Spores are monolete, ellipsoid, and with broadly winged perispore. Germination is Vittaria-type and the prothallial development is Aspidium-type. Adult gametophytes are cordiform-spatulate to cordiform-reniform, with marginal and superficial trichomes. Gametangia are of the type commonly found on leptosporangiate homosporous ferns. Differences between the two species of genus include size of the spores, width of the perispore, germination time, size of the trichomes, and time of formation of the gametangia. These two species share some features with some species of Arachniodes, Cyrtomium, Dryopteris, Phanerophlebia, and Polystichum, such as type of germination and prothallial development and trichomes. They differ from Didymochlaena truncatula, which has prothallial development of the Adiantum-type and lacks trichomes on the sexual phase.