A comparative study of gametophyte morphology, gametangial ontogeny, and sex expression in the Asplenium adiantum-nigrum complex (Aspleniaceae, Pteridophyta). - Prada, ,C.,.; Pangua, ,E.,.; Pajarón, ,S.,.; Herrero, ,A.,.; Escudero, ,A.,.; and Rubio, ,A.. (Annales Botanici Fennici, 1995)