Sexual phase development was studied in Didymochlaena truncatula, on the basis of spores collected in Península Moreno and Tebanca, Catemaco, Veracruz, México. The spores are monolete, ellipsoid, with perine, and non-clorophyllic. The germination pattern is of the Vittaria-type and the prothallial development is of the Adiantum-type, the adult gametophytes are cordiform to reniform and without trichomes; the gametangia are typical of the leptosporangiate ferns. The first leaf of the sporophyte appears 100 days after the sowing of the spores, the lamina is spatulate, with dichotomous venation and short capitate, unicellular marginal hairs.
Keywords: didymochlaena, dryopteridaceae, gametophyte, México, morphogenesis, prothallus, pteridophyta