Abstract Athyrium decurtatum var. platense (= Thelypteris decurtata subsp. platensis) is transferred to the genus Amauropelta and raised to the species level based on morphological, palynological and geographical evidences. This fern species is endemic to the Delta of Paraná district, belonging to the Esteros del Iberá biogeographic province in the Southern Cone of South America.

Resumo Athyrium decurtatum var. platense (= Thelypteris decurtata subsp. platensis) é transferida para o gênero Amauropelta e elevada ao nível de espécie com base em estudos morfológicos, palinológicos e geográficos. Esta espécie é endêmica do distrito Delta do Paraná, pertencendo à província biogeográfica dos Esteros del Iberá, no Cone Sul da América do Sul.

Abstract The recovery of soil spores is a strategy to strengthen in decline or disappeared populations from natural environments. In this work, we analyzed 25 soil samples extracted from a patch of gallery forest in an “albardón” of Punta Lara Reserve, Buenos Aires. The samples were distributed in 50 Petri dishes, 25 exposed to controlled temperature and light and another 25 kept in darkness. To contribute to the identification of gametophytes and sporophytes, spores of the local species were cultured in vitro. In 18 months of trial, the appearance of gametophytes and sporophytes was observed, in a greater proportion those belonging to a dominant species in the community: Doryopteris concolor. Numerous gametophytes and sporophytes from Gastoniella chaerophylla were also obtained, a taxon not found in the “albardón” for two years. The germination index (GI) was estimated and the morphological characteristics of the gametophytes and sporophytes were recorded. This is the first contribution to the knowledge of the spore banks in Argentina, in a protected area where several threats put at risk the survival of native species. The bases to implement methods of ex situ and in situ conservation of native ferns are provided.

Resumen La recuperación de esporas del suelo es una estrategia para reforzar poblaciones en disminución o desaparecidas de los ambientes naturales. En este trabajo se analizaron 25 muestras de tierra extraídas de un parche de selva en galería en un albardón de la Reserva Punta Lara, Buenos Aires. Las muestras fueron distribuidas en 50 cápsulas de Petri, 25 expuestas a temperatura y luz controladas y otras 25 mantenidas en oscuridad. Para contribuir a la identificación de los gametofitos y esporofitos se cultivaron in vitro esporas de las especies del lugar. En 18 meses de ensayo se observó la aparición de gametofitos y esporofitos, en mayor proporción los pertenecientes a una especie dominante en la comunidad: Doryopteris concolor. Se obtuvieron además numerosos gametofitos y esporofitos de Gastoniella chaerophylla, un taxón no encontrado en el albardón desde hace dos años. Se estimó el índice de germinación (IG) y se registraron las características morfológicas de los gametofitos y esporofitos. Esta es la primera contribución al conocimiento de los bancos de esporas en Argentina, en un área protegida donde diversas amenazas ponen en riesgo la supervivencia de especies nativas. Se brindan las bases para implementar métodos de conservación ex situ e in situ de los helechos nativos.

Resumen Pleopeltis macrocarpa y Microgramma mortoniana son dos helechos epífitos de la familia Polypodiaceae hallados con baja frecuencia en la Reserva Natural Punta Lara (Buenos Aires, Argentina). El objetivo de este trabajo fue estudiar la morfogénesis de gametófitos epífitos para fortalecer poblaciones vulnerables y contribuir a su conservación. Se recolectaron hojas fértiles. Las esporas se sembraron en placas de Petri con medio de cultivo Dyer. Las esporas se caracterizaron por ser monoletes, elipsoidales, amarillentas y con ornamentación verrucosa. La germinación fue del tipo Vittaria y el desarrollo del gametofito es del tipo Drynaria. El esporofito de P. macrocarpa surgió a los 500 días y el de M. mortoniana a los 120. El patrón de germinación, el desarrollo del gametofito, el glóbulo lipídico en la célula protálica y los pelos unicelulares capitados en el margen podrían considerarse en la sistemática del grupo. La demora en la formación de esporofitos a través de la reproducción sexual, permite inferir que el éxito de su propagación estaría sujeto a la reproducción vegetativa.

Abstract The Punta Lara Natural Reserve is located on the riverside of the La Plata River in the province of Buenos Aires, Argentina. It is the Southernmost relict in the world of subtropical riparian forest. The epiphytic ferns studied in this work belong to the Polypodiaceae family: Microgramma mortoniana and Pleopeltis macrocarpa. Plant communities are subject to high levels of anthropization and introduction of exotic species. The goals of this work are to provide information on the morphogenesis of epiphytic gametophytes and to extend knowledge of their life cycles, contributing to their conservation. Sowing was carried out in Dyer medium. In both species the spores are monolete, ellipsoidal, yellowish and with verrucate sculpture. The equatorial diameter is 60-61 μm, the polar diameter is 39-42 μm. The germination is the Vittaria type; in M. mortoniana occurs at 20 days, while in P. macrocarpa occurs at six days. The filaments are uniseriate of 3-6 cells in length. The gametophyte development is Drynaria type. The cordated form is given after 40 days. In M. mortoniana, buds originated after 40 days. In P. macrocarpa, after 120 days, clathrate trichomes scale-like appear mainly on the margins of the gametophyte. The gametangia are typical of leptosporangiate ferns. The sporophyte of M. mortoniana emerged after 120 days and that of P. macrocarpa arose after 500 days, its blades are simple, spatulate and unicellular and multicellular branching hairs were observed. The germination pattern, gametophyte development, the presence of a lipid globule in the prothalic cell and the formation of unicellular capitated hairs are relevant characters that could be considered for systematic group. The delay in the formation of sporophytes through sexual reproduction, allows us to infer that the success of their establishment in situ would be given by the vegetative reproduction through creeping rhizomes and buds of gametophytes. Rev. Biol. Trop. 66(3): 1078-1089. Epub 2018 September 01.