Palynological analysis of Dennstaedtiaceae taxa from the Paranaense Phytogeografic Province that produce monolete spores and its systematic implications (I): Blotiella lindeniana, Histiopteris incisa and Paesia glandulosa

ABSTRACT The genera of Dennstaedtiaceae have sporophytes with very different morphological characteristics between each other, and this feature has made difficult the systematic circumscription of the family. This reason makes necessary the study of new characters that allow a better understanding of the relations within the group. The spore morphology and wall structure of Blotiella lindeniana, Histiopteris incisa and Paesia glandulosa from the Paranaense Phytogeographic Province were studied using light microscope, and scanning and transmission electron microscope. The exospore has two layers and, according to the species, the exospore surface bears pila, echinae, verrucae, bacula and tubercles. The perispore has two or three layers and its surface is psilate, baculate or rugulate. The variability found in the sculpture of the spores and their stratification and ultrastructure of perispore reflects the morphological differences observed in the sporophyte of the species studied. Additionally, while the stratification and ultrastructure of the exospore is shared by the Dennstaedtiaceae species, their ornamentation could be a character to distinguish species into the clade "hypolepidoide". The finding of spores with similar characteristics in phylogenetically unrelated families allows us to suggest that palynological features do not have an evolutionary value to establish relationships between groups above the genus level.

Diversidad de helechos y licófitas de la Reserva Natural Punta Lara, Buenos Aires, Argentina

Diversity of ferns and lycophytes from Reserva Natural Punta Lara, Buenos Aires , Argentina. Punta Lara Natural Reserve shelters the relict of the Southernmost riparian forest in the world, where the flora is threatened by the anthropic expansion and by the introduction of exotic species. In this area the ferns and lycophytes grow in particular environments as marshland, grassland and marginal forest. The aim of this work was to evaluate the diversity of ferns and lycophytes that inhabit in Punta Lara Natural Reserve. Field trips were conducted from 2006 to 2009 and local herbaria and specific bibliography were also revised. As a result of our study twenty four taxa of ferns and lycophytes were recognized. Their habit was mainly terrestrial (70%), fewer aquatic (17%) and epiphytic (13%). Five native taxa were scarcely recorded whereas two native species previously documented were not found. We assume that the main threats on ferns and lycophytes populations in Punta Lara Reserve are: removal for comercialization, invasion by exotic species and climatic fluctuations (drought periods). Keys for taxa identification are given and strategies for the conservation of threatened taxa are proposed. Rev. Biol. Trop. 59 (3): 1037-1046. Epub 2011 September 01.

Hasta el año 1987 el número de helechos y licofitas citados para la Reserva Punta Lara era de 30, incluyendo taxa específicos e infraespecíficos. El objetivo de este trabajo fue evaluar la diversidad de los helechos y licofitas que crecen en esta reserva, donde se halla el relicto más austral de las selvas en galería. Para llevar a cabo este estudio se realizaron viajes de campo durante los años 2006-2009 y se consultaron herbarios locales así como bibliografía especializada. Como resultado del estudio se determinaron 24 taxa de helechos y licofitas, de hábito predominantemente terrestre (70%); pocas acuáticas (17%) y epífitas (13%); dos especies exóticas, mientras que otras dos especies nativas citadas previamente no fueron halladas. Cinco taxa fueron registrados con escasa frecuencia. Se infiere que las principales causas de amenaza para las poblaciones de licofitas y helechos en la Reserva Natural Punta Lara son la extracción para su comercialización, la introducción de plantas exóticas y las fluctuaciones climáticas (periodos de sequía). Se presenta una clave de identificación de los taxa registrados y se plantean futuras estrategias de conservación de las especies consideradas vulnerables.