Resumen Arana, M. D.; M. L. Luna, M. A. Ganem & G. E. Giudice. 2022. Caracterización de Asplenium achalense (Aspleniaceae), una especie poco comprendida de la flora argentina: evidencias morfológicas, palinológicas y distribucionales. Darwiniana, nueva serie 10(2): 527-536. Asplenium (Aspleniaceae) es uno de los géneros de helechos más complejos desde el punto de vista taxonómico, con unas 700 especies, de distribución casi cosmopolita. En Argentina, Asplenium constituye el género de helechos más rico en especies, con 38 taxones. Entre esas especies, la delimitación de Asplenium achalense sigue estando escasamente comprendida. Algunos autores consideran a A. serra como una variante de A. achalense, o incluso la última especie ha sido considerada como un complejo de especies. El hallazgo de una población de Asplenium achalense en Yungas después de tres décadas sin observaciones en la naturaleza y de no registrarse ejemplares de herbarios más recientes, hizo posible analizar material vivo y observar nuevos caracteres diagnósticos presentes en raquis y escamas de láminas, pelos glandulares en pecíolos y raquis, junto con características de la pared de las esporas, que son críticos para delimitar A. achalense como un taxón bien definido, endémico del Noroeste hasta el centro de Argentina.

Abstract Arana, M. D.; M. L. Luna, M. A. Ganem & G. E. Giudice. 2022. Characterizing Asplenium achalense (Aspleniaceae), a misunderstood species of Argentine flora: morphological, palynological and distributional evidences. Darwiniana, nueva serie 10(2): 527-536. Asplenium (Aspleniaceae) is taxonomically one of the most complex fern genera with about 700 species, nearly cosmopolitan in distribution. In Argentina, Asplenium constitutes the most species- rich fern genus, with 38 taxa. Among these species, the delimitation of Asplenium achalense remain poorly understood. Some authors consider A. serra as a variant of A. achalense, or even the last species has been considered as a complex of species. The finding of a population of Asplenium achalense in Yungas after three decades without observations in the wild and neither registering more recently herbarium specimens, made it possible to analyse living material and observe new diagnostic characters present in rachises and laminae scales, glandular hairs in petioles and rachises along with spore wall features, that are critical to delimitate A. achalense as a well-defined taxon, endemics of north-west to central Argentina.

Summary Background and aims : The morphological characteristics of the spores provide information for the identification of fern taxa. To deepen the analyses of the morphological characteristics of the spores of the isosporated ferns inhabiting the Punta Lara Nature Reserve using light microscopy. M&M : The spores of the isosporate ferns that grow in the Punta Lara Nature Reserve (Buenos Aires Province, Argentina) were studied under a light microscope. The study was carried out with fresh materials collected during three years (2016-2018) at different sites of the Reserve. Twenty fern taxa, 16 native and 4 exotic, were analysed. The registered characteristics were: colour, shape, major and minor equatorial diameters, polar diameter, length and characteristics of the laesura and wall ornamentation. Results : The colour of the spores may be yellow, light brown, dark brown and only in Equisetum they are green (chlorophyllous). Most spores are monolete (13 species), other trilete (6 species) and only one species has alete spores. The spore walls may be smooth, wrinkled, folded, verrucated, tuberculated, reticulated and winged. Conclusions : The morphology of the spores allows the identification of the ferns of the Reserve at a generic and specific level and provides information for palaeopalynological and aeropalynological studies and of soil spore banks.

Resumen Introducción y objetivo : Las características morfológicas de las esporas brindan información para la identificación de taxa de helechos. Profundizar los análisis de las características morfológicas de las esporas de los helechos isosporados que habitan en la Reserva Natural de Punta Lara utilizando microscopía óptica. M&M : Se estudiaron con microscopio óptico las esporas de helechos isosporados que crecen en la Reserva Natural Punta Lara (provincia de Buenos Aires, Argentina). El estudio fue llevado a cabo con material fresco colectado durante 3 años (20162018) en diferentes sitios de la Reserva. Se analizaron 20 taxa de helechos, 16 nativos y 4 exóticos. Las características registradas fueron: color, forma, diámetros ecuatoriales mayor y menor, diámetro polar, longitud y características de la lesura y ornamentación de la pared. Resultados : El color de las esporas puede ser amarillo, castaño claro, castaño oscuro y solo en el caso de Equisetum son verdes (clorofílicas). La mayoría de esporas son monoletes (13 especies), otras triletes (6 especies) y una sola especie posee esporas aletes. Las paredes de las esporas pueden ser lisas, plegadas, verrucosas, tuberculadas, reticuladas y ruguladas-crestadas. Conclusiones : La morfología de las esporas permite la identificación de los helechos de la Reserva a nivel de género y especie y aporta información para estudios paleopalinológicos, aeropalinológicos y de bancos de esporas del suelo.

Abstract The spore morphology and wall ultrastructure of Dryopteris filix-mas, D. patula and D. wallichiana from Argentina were studied using light microscope, scanning and transmission electron microscope. The study was carried out with herbarium material from Argentine institutions. Equatorial diameters, polar diameters and laesura length were measured. The spores are monoletes with a rugate ornamentation. The folds are short to long, inflate, irregular in shape and size, and varying from subglobose to elongate. The perispore surface is rugulate. The exospore of all the species analyzed is two-layered in section. Simple and branched channels are also present. The perispore is composed of two layers, the inner one forms the ornamentation and the outer covers all the outer and inner surfaces. Some abnormalities, such as globose, triangular or twisted spores were observed. The morphology and ultrastructure of the species are very similar. The differences observed are related to the length and thickness of the perispore folds. The characteristics of these spores would not provide relevant information to differentiate species or sections within the genus, but can provide information for phylogenetic studies as well as for alterations in the biological cycles.

Background and aims: The morphology and the anatomy of the petioles provide useful information for taxonomic issues in ferns. The aim of this study was to analyze the diagnostic characters of petioles in 37 species of Asplenium that grow in Argentina, to contribute to their identifcation and to ascertain on their adaptive signifcance. M&M: Herbarium specimens and fresh material were employed. Materials were analyzed under stereoscopic and light microscopes; in the latter case, the samples were processed following the conventional histological techniques. The characters analyzed were: colour, length, presence of wings, sub-epidermic mechanical tissue, aeration lines, circumendodermal band (CB), shape and number of vascular bundles and xylem contour. Results: Some characteristics of the petioles allow the grouping of species. The diagnostic features are: colour, presence/absence of wings, number of vascular bundles, bundles contour, xylem contour and presence/absence of CB. Conclusions: Petiole characters alone do not allow the identifcation of the taxa at specifc level, although along with others they contribute to the systematics of the genus. The anatomy of the petiole does not show in general terms relationship with the habit of these plants. The type and distribution of subepidermic mechanical tissue and the presence of CB are associated with species that inhabit exposed and dry environments, but these features are not exclusive of the taxa that grow under these conditions.

Introducción y objetivos: Las características externas e internas de los pecíolos brindan información útil para los estudios taxonómicos en helechos. El objetivo de este trabajo fue analizar los caracteres diagnósticos del pecíolo en las 37 especies de Asplenium que crecen en Argentina, para contribuir a su identifcación e indagar sobre su signifcado adaptativo. M&M: Se emplearon especímenes de herbario y material fresco. Los materiales se analizaron con microscopios estereoscópico y óptico; en el último caso las muestras fueron procesadas siguiendo las técnicas histológicas convencionales. Los caracteres analizados fueron: color, longitud, presencia de alas, tejido mecánico sub-epidérmico, líneas de aireación, banda circumendodermal (BC), forma y número de los haces vasculares y contorno del xilema. Resultados: Algunas características de los pecíolos permiten el agrupamiento de especies. Los caracteres diagnósticos son: color, presencia/ausencia de alas, número de haces vasculares, contorno de los haces, contorno del xilema y presencia/ausencia de BC. Conclusiones: Los caracteres del pecíolo por si solos no permiten la identifcación de los taxa a nivel específco, si bien junto con otros contribuyen a la sistemática del género. La anatomía del pecíolo no evidencia en general relación con el hábito de estas plantas. El tipo y la disposición del tejido mecánico sub-epidérmico y la presencia de BC se asocian a especies que crecen en ambientes expuestos y secos, pero no son exclusivos de los taxa que crecen bajo estas condiciones.

First record of Asplenium harpeodes (Aspleniaceae) for the Argentinian flora. The first finding of Asplenium harpeodes in Argentina is disclosed. This species was found growing in Jujuy and Salta provinces, inhabiting the Yungas. A description and an illustration are given, and information about its distribution and the habitat is provided. A key to differentiate this species from nearby ones with pinnate lamina is also presented.

Se da a conocer el primer hallazgo de Asplenium harpeodes para la Argentina. Esta especie crece en las provincias de Jujuy y Salta, en las Yungas. Se presenta la descripción e ilustración del taxón y se brindan datos de su distribución y hábitat. Se brinda una clave para diferenciar esta especie de las más afines con lámina pinnada.

A review of the Hymenasplenium species from Argentina is presented and their morphology and palynology are analyzed. Two species are recognized: H. laetum growing in Misiones, Salta and Tucumán, of terrestrial habit, and H. triquetrum which grows as saxicolous in Misiones. For both species, iconographies, descriptions, and distribution maps, are given. The diagnostic value of characteristics of the root inner cortex to differentiate both genera of Aspleniaceae, and the presence of two types of spores ornamentation in Hymenasplenium, are corroborated. Illustrations of the morphological features of the roots, petioles, and spores are presented.

Se presenta una revisión de las especies del género Hymenasplenium de Argentina y se analizan aspectos morfológicos y palinológicos. Se identificaron dos especies: H. laetum que crece en Misiones, Salta y Tucumán, de hábito terrestre, e H. triquetrum que crece como saxícola en Misiones. Para cada especie se incluye iconografía, descripciones y mapa de distribución. Se corrobora el valor diagnóstico de las características de la corteza interna de la raíz para diferenciar los dos géneros de Aspleniaceae y la presencia en el género Hymenasplenium de dos tipos de ornamentación de esporas. Se presentan ilustraciones de raíces y pecíolos, y de las esporas analizadas.

O gênero Lygodium Sw. é um das poucas samambaias trepadoras no mundo. Os esporos de L. venustum Sw. e L. volubile Sw. foi estudados com microscopias de luz e eletrônicas de transmissão e varredura. Este trabalho é baseado em material de herbário. Os esporos são trilete, triangular com lados retos para convexo em vista polar. O equatorial diâmetro é 72-104 µm e o diâmetro polar é 64-84 µm. O ornamentação em L. venustum é verrucose-tuberculoso enquanto em L. volubile é verrucose-tuberculoso no proximal cara e com poucos cume no distal cara, em que um micro-ornamentação constituída por verrugas e tubérculos é observado. Um cume equatorial também está presente. O exosporo é de dois camadas, em L. venustum é liso em contraste com o exosporo ornamentado de L. volubile. O perisporo é similar nas duas espécies analisadas. Esta parede é de quatro camadas com elementos particulares dispostas radialmente na camada do meio. Nas superfícies de esporos de ambas espécies poucos spheroids é observado. Os resultados apresentados no presente estudo podem ser útil para o sistemática do gênero bem como para propósitos filogeneticos.

The genus Lygodium Sw. is one of the few climbing ferns in the world. The spores of L. venustum Sw. and L. volubile Sw. were studied using light, scanning, and transmission electron microscopy. This work is based on herbarium material. The spores are trilete, triangular, with straight to convex sides in polar view. The equatorial diameter is 72-104 µm, and the polar diameter is 64-84 µm. The ornamentation in L. venustum is verrucate-tuberculate while in L. volubile, it is verrucate-tuberculate in the proximal face but with a few ridges on the distal face, where a micro-ornamentation constituted by verrrucae and tubercles is observed. An equatorial ridge is also present. The exospore is two-layered; in L. venustum, it is smooth in contrast with the ornamented exospore of L. volubile. The perispore of the two species analyzed is similar. This wall is four-layered with particular elements arranged radially in the middle layer. On the spores surface of both species, few spheroids are observed. The results introduced in the current study may be useful for the systematics of the genus as well as for phylogenetic purposes.

The aim of this contribution is to provide a preliminary evaluation of the endangered species of ferns and Lycophyta that inhabit Argentina, in order to recommend strategies for their conservation. For this purpose, we considered the endemic taxa as well as those which grow in reduced areas from neighboring countries. Categories (from 1 to 5) were assigned according to the PlanEar procedure, taking into account the distribution of the taxa and their relative abundance or rarity. As a result of this study, 18 of 34 endemic taxa of ferns and Lycophyta growing in Argentina were considered endangered (categories 4, 4-5, 5). The main cause of flora threat is loss or degradation of habitats by human activities, which affect the survival of many endemic plants from Argentina. Integrated strategies for conservation, emphasizing in situ preservation in their natural habitats, together with ex situ conservation by means of spore banks are suggested.

El objetivo de esta contribución es realizar una evaluación preliminar del grado de amenaza de los helechos y Lycophyta que crecen en Argentina, con el fin de proponer estrategias para su conservación. Para ello se tuvieron en cuenta los taxa endémicos así como aquellos que crecen en áreas reducidas de países limítrofes. Las categorías (1 a 5) fueron asignadas de acuerdo con las propuestas por el PlanEar, considerando el área de distribución y su abundancia relativa o rareza. Como resultado de este estudio, 18 taxa de helechos y Lycophyta de Argentina fueron considerados amenazados (categorías 4, 4-5, 5), de un total de 34 taxa endémicos. La principal causa de amenaza de la flora en esta región es la pérdida o degradación del hábitat por las actividades humanas, poniendo en riesgo la supervivencia de muchos taxa endémicos. Se sugieren estrategias combinadas de conservación, con énfasis en la protección in situ junto con la conservación ex situ en bancos de esporas.

The ferns and licophytes from the National Park Lago Puelo, Chubut, Argentina were studied. We registered 47 taxa with 12 of them new records for the province of Chubut and 1new to Patagonia. A high taxonom-ic diversity was observed, with about 50 % of the Patagonian fern flora represented. Some of the taxa are growing exclusively in this area and in Chile at the same latitudes. The Puelo pass, which is connect-ing Argentina and Chile, at the lowest altitude of the North- Patagonian Andes, constituted a penetrating route of Valdivian species. The presence of pasture livestock, the invasion of exotic plants and the latent fires, are the principals dangers for the survival of the Flora in this area. Therefore these areas of the Subantartic Forest merit special attention for conservation. A taxonomic key is included and a distribu-tion map that shows the areas of highest diversity of ferns and lycophytes within the national park is given. For each taxon the geographical distribution and ecology data are also given.

Se estudiaron los helechos y licofitas presentes en el Parque Nacional Lago Puelo, Chubut, Argentina. Se determinó la presencia de 47 taxa, de los cuales 12 constituyen nuevos registros para la Provincia de Chubut y 1 para la Región Patagónica. Se observó una elevada diversidad taxonómica, representando más del 50 % de la flora patagónica. Varios de los taxa crecen exclusivamente en el área y en Chile a iguales latitudes. El paso Puelo, que conecta Argentina y Chile, es el más bajo de la Cordillera de los Andes en Norpatagonia y es vía de ingreso de especies valdivianas. La presencia de animales de pastoreo, invasión de plantas exóticas y el riesgo latente de incendios, significan un peligro para la supervivencia de la flora del Parque. Todas estas características hacen que estas áreas de los Bosques Subantárticos merezcan una especial atención para su conservación. Se presentan claves para la determinación de los taxa y un mapa de ubicación de las áreas de mayor diversidad de helechos y licofitas dentro del parque. Para cada taxón registrado se da la distribución geográfica y datos ecológicos en el área de estudio.

A morfologia dos esporos e a ultraestrutura da parede de Sphaeropteris gardneri (Hook.) R.M. Tryon, Brasil, foram analisadas com MO, MEV e MET. Os esporos são trilete com uma ornamentação formada por cristas curtas e baixas e com espinhos em suas margens. O exosporo possui 2,5μm de espessura, duas camadas em secção e estão presentes canais simples ou ramificados. A camada interna possui três estratos: o estrato interno é formado por uma rede de filamentos ramificados e fusionados, o estrato médio tem fios com uma orientação radial e no estrato externo fino, fibras escuras estão imersas em uma matrix menos densa. A outra camada do perisporo é a que forma as cristas equinatas e é constituída de filamentos dispostos em um arranjo compacto. Glóbulos de diferentes tamanhos são observados na superfície. As diferenças encontradas na ornamentação do perisporo e na ultraestrutura do Alsophila estudado previamente e aqueles de Sphaeropteris mostram uma tendência à complexidade da parede.

The spore morphology and wall ultrastructure of Sphaeropteris gardneri (Hook.) R.M. Tryon from Brazil were analyzed with LM, SEM and TEM. The spores are trilete with an ornamentation formed of short low ridges with spines in their margins. The exospore is 2.5μm thick, two- layered in section and single or branched channels are present. The perispore is 1.2μm thick and two-layered. The inner layer has three strata: the inner stratum is formed of a network of branched and fused threads, the middle stratum has threads with a radial orientation and in the outer stratum thin, dark fibres are immersed in a less dense contrasted matrix. The outer layer of the perispore is the one that forms the echinate-ridges and is constituted of threads arranged in a compact way. Globules of different sizes are observed on the surface. The differences found in the perispore ornamentation and ultrastructure in Alsophila, which was previously studied, and those of Sphaeropteris, show a tendency to wall complexity.

Cyathea atrovirens (Langsd. & Fisch.) Domin is reported for the first time for Corrientes province (Argentina). Thus, its area of distribution is extended southwest. The presence of Alsophila odonelliana (Alston) M. Lehnert is confirmed for Jujuy province (Argentina). In this study the spore features were diagnostic in order to determine these taxa.

Cyathea atrovirens (Langsd. & Fisch.) Domin se cita por primera vez para la provincia de Corrientes (Argentina). De esta manera se extiende su área de distribución hacia el sudoeste. Además se confirma la presencia de Alsophila odonelliana (Alston) M. Lehnert en la provincia de Jujuy (Argentina). En este estudio los caracteres de las esporas resultaron diagnósticos para la determinación genérica de los taxa.

Nine families, 29 genera and 52 species and infraespecific taxa of Pteridophytes are reported for the nature reserve "Cuñá Pirú". The most represented genus is Asplenium with eight species, two of them being new records for the Argentinean flora. Between one to three species were recorded for the remaining genera. These plants mainly grow deep into the forest, or along forest trails and stream banks. Keys to all groups and entities, literature, distribution and ecology references are included.

En la Reserva "Cuñá Pirú" se registraron un total de 9 familias, 29 géneros y 52 especies y taxones infraespecíficos. El género mejor representado es Asplenium con 8 especies, dos de ellas novedades para la flora argentina. El resto de los géneros tienen 1-3 especies. Estas plantas se hallan preferentemente en el interior de la selva y en el borde de los caminos y arroyos. Se presentan claves dicotómicas para la determinación de los grupos y entidades, como así también referencias bibliográficas, distribucionales y ecológicas.

Blechnum cordatum (Desv.) Hieron. is recorded for the first time from the Province of Salta, North-West Argentina. The species is described and illustrated and its geographical distribution in South America is also given.

Se registra por primera vez para el Noroeste de Argentina, en la Provincia de Salta, a Blechnum cordatum (Desv.) Hieron. Se describe e ilustra a la especie y se da a conocer su distribución geográfica en América del Sur.