Abstract Lycophytes show no instances of ectomycorrhizas. Phlegmariurus saururus is the only Huperziaceae that grows in Comechingones biogeographic province, in sunny, exposed surficial rock crevices with poor soil development and very scarce water. As mycorrhizas improve plant fitness in natural ecosystems, it was hypothesized that P. saururus can develop multiple types of fungal symbiosis, including ectomycorrhizas. For detecting, identification and description of mycorrhizas, conventional techniques were employed, and samples of roots were cut with an ultra-microtome to obtain thin (3 µm) and ultrathin (0.1 µm) sections. Phlegmariurus saururus is the first species of Lycopodiopsida where the ectomycorrhizas are evidenced. Arbuscular mycorrhizas and septate endophytes were also found. Ectomycorrhizas can alter the anatomy and hydrophilic properties of roots, improving the adaptation of the plant hosts to habitats with a marked period of drought, as the novel Andean Comechingones habitats. The ectomycorrhizas detected in P. saururus could be considered as an adaptive mechanism related to the successful colonisation of this habitat and can undergo a significant transformation in the lifestyle of fungal symbiosis of lycophytes, which could provide important insights into this morphological and functional evolution.

Summary Background and aims: The Sierras Pampeanas Centrales of Argentina constitute the fourth centre of diversity of lycophytes and ferns in the Cono Sur, where representatives of four families of lycophytes live: Huperziaceae, Lycopodiaceae, Isoetaceae and Selaginellaceae. The aim of this work is to provide data of the morphology of their spores observed with optical and scanning electron microscopes, as a contribution to the taxonomy and conservation. M&M: The materials were analysed without prior chemical treatment and photographic records were obtained with both observation equipments. Results: The morphological diagnostic features of the spores are presented. The Huperziaceae and Lycopodiaceae are isosporous with trilete spores. Huperziaceae presents foveolated or fossulated spores, while Lycopodiaceae spores are reticulate, scabrate and baculate. In Isoetes hieronymi (heterosporate), the microspores are monolete with echinate ornamentation, while the megaspores are trilete, with reticulate ornamentation. The Selaginellaceae, all heterosporate, produce trilete microspores and megaspores, both with varied ornamentation. Conclusions: Spore characteristics provide relevant information for regional floristic studies as well as for taxonomic assignments, both of extant flora and fossil records. Also, for studies of the composition of soil spore banks as a tool for the conservation of local floristic biodiversity.

Resumen Introducción y objetivos: Las Sierras Pampeanas Centrales de Argentina constituyen el cuarto centro de diversidad de licofitas y helechos del Cono Sur, donde habitan representantes de cuatro familias de Licofitas: Huperziaceae, Lycopodiaceae, Isoetaceae y Selaginellaceae. El objetivo de este trabajo es aportar datos sobre la morfología de las esporas observadas con microscopios óptico y electrónico de barrido como contribución a la taxonomía y conservación. M&M: El material fue analizado sin tratamiento químico previo y se obtuvieron registros fotográficos con ambos equipos de observación. Resultados: Se presentan las características diagnósticas de la morfología de las esporas. Las Huperziaceae y Lycopodiaceae son isosporadas con esporas triletes. Huperziaceae presenta esporas foveoladas o fosuladas, mientras que en las Lycopodiaceae las esporas son reticuladas, escabradas y baculadas. En Isoetes hieronymi (heterosporada), las microsporas son monoletes con ornamentación equinada, en tanto que las megasporas son triletes, con ornamentación reticulada. Las Selaginellaceae, todas heterosporadas, producen microsporas y megasporas triletes, ambas con ornamentación variada. Conclusiones: Las características de las esporas aportan información relevante para estudios florísticos regionales así como para asignaciones taxonómicas, tanto de la flora actual como de registros fósiles. También, para estudios de la composición de los bancos de esporas del suelo como herramienta para la conservación de la biodiversidad florística local.

summary Background and aims: The status of the presence of arbuscular mycorrhizal fungi (AMF) in lycophytes and ferns has been analysed in 11% of them. This work aims to characterise and quantify the AMF colonisation and to characterise septate endophytes present on the roots of the Thelypteridaceae: Amauropelta jujuyensis, A. nubicola, and Pelazoneuron patens. M&M: Ten individuals per species were collected in August 2022. Conventional staining and techniques were used to estimate colonisation. Results: The root of Amauropelta jujuyensis, A. nubicola, and Pelazoneuron patens showed AMF with Arum and Paris morphological types simultaneously. The hyphal colonization showed no significant difference among species, arbuscular colonization was significantly higher in A. jujuyensis, while vesicular colonization was considerably higher in A. nubicola. In addition, septate endophytes were evident in the species of the genus Amauropelta. Conclusión: The association of AMF and other fungal endophytes with the native Argentine Thelypteridaceae Amauropelta jujuyensis, A. nubicola, and Pelazoneuron patens is evidenced for the first time in riparian environments of the Yungas. The coexistence of Arum and Paris morphological types in the three studied fern species is demonstrated.

Resumen Introducción y objetivos: El estatus de la presencia de hongos micorrícicos arbusculares (HMA) en licofitas y helechos se ha analizado en un 11 %. El objetivo de este trabajo es caracterizar y cuantificar la colonización de los HMA y caracterizar endófitos septados en raíces de las Thelypteridaceae: Amauropelta jujuyensis, A. nubicola y Pelazoneuron patens. M&M: Se recolectaron 10 individuos por especie en agosto del 2022. La colonización se estimó utilizando técnicas y tinción convencionales. Resultados: Las raíces de Amauropelta jujuyensis, A. nubicola y Pelazoneuron patens presentaron HMA de tipo morfológico Arum y Paris, simultáneamente. La colonización hifal no mostró diferencia significativa entre las especies, la arbuscular evidenció un porcentaje significativo mayor en A. jujuyensis y la vesicular fue mayor en A. nubicola. Además, se evidenciaron endófitos septados en las especies analizadas del género Amauropelta. Conclusiones: Se evidencia, por primera vez en ambientes riparios de las Yungas, la asociación de los HMA y otros endófitos fúngicos con Amauropelta jujuyensis, A. nubicola y Pelazoneuron patens. Se demuestra en estas la coexistencia de los tipos morfológicos Arum y Paris.

Summary Background and aims: Ferns are sensitive to environmental changes, inhabiting ecosystems susceptible to degradation. Spore banks and in vitro spore culture are useful tools employed in their conservation. The objective was to test the ability of the spores to germinate after being stored in a freezer and to develop gametophytes and sporophytes, in native fern species of genera Amauropelta, Blechnum and Physematium. M&M: Spores of A. argentina, B. auriculatum and P montevidensis were stored at -20 °C in dry conditions for 6 and 12 months. They were sown in vitro in Dyer liquid medium and incubated in a growth chamber. The means of germination percentages were calculated and a one-way Student's t-test was employed. Gametophyte and sporophyte development was registered under light and stereoscopic microscopes. Results: Depending on the species, statistical differences were recorded in germination percentages (viability) between both storage periods. The spores of A. argentina kept in freezer for 12 months completely lost viability. In B. auriculatum, viability decreased over time, and in P. montevidensis it remained constant. Gametophytes and sporophytes developed in all cultures; except in A. argentina spores, with 12 months in freezer. Conclusions: The viability of the spores under dry storage at low temperature could be conditioned by the ecological requirements of the species. Protocols used for spore storage and culture allowed obtaining gametophytes and sporophytes in trials.

Resumen Introducción y objetivos: Los helechos son sensibles a cambios ambientales, habitando en ecosistemas susceptibles a degradación. Los bancos de esporas y el cultivo in vitro son herramientas útiles para su conservación. El objetivo fue probar la capacidad de las esporas para germinar luego del almacenamiento en freezer y de desarrollar gametofitos y esporofitas, en especies de helechos nativos de los géneros Amauropelta, Blechnum y Physematium. M&M: Esporas de A. argentina, B. auriculatum y P. montevidensis se almacenaron deshidratadas a -20 °C durante 6 y 12 meses. Se sembraron in vitro en medio Dyer líquido y se incubaron en estufa. Se calcularon las medias de los porcentajes de germinación y se empleó una prueba t Student unidireccional. El desarrollo de gametofitos y esporofitas fue registrado con microscopio óptico y lupa. Resultados: Se registraron diferencias estadísticas en los porcentajes de germinación (viabilidad) entre ambos períodos de almacenamiento. Las esporas de A. argentina mantenidas durante 12 meses en freezer perdieron completamente la viabilidad. En B. auriculatum, la viabilidad disminuyó con el tiempo y en P. montevidensis que permaneció constante. Se desarrollaron gametofitos y esporofitas en todos los cultivos; excepto en A. argentina almacenadas 12 meses en freezer. Conclusiones: La viabilidad de esporas almacenadas deshidratadas a baja temperatura podría estar condicionada por los requerimientos ecológicos de las especies. Los protocolos utilizados para el almacenamiento y cultivo de esporas permitieron obtener gametofitos y esporofitas en todos los ensayos.

RESUMEN Se cita a Adiantopsis orbygniana (Pteridaceae) por primera vez para la flora de Tucumán, Argentina, en la provincia biogeográfica de las Yungas (distrito de las Selvas de transición). Éste constituye el registro más austral de la especie. Se proporciona una descripción actualizada, se ilustra con fotografías y se aportan las características del ambiente donde habita. La presencia de A. orbygniana en las Yungas apoyaría la hipótesis de fragmentación de las selvas sudamericanas por la cuña árida chaqueña.

ABSTRACT Adiantopsis orbygniana (Pteridaceae) is recorded for the first time for Tucumán flora, Argentina, in the Yungas biogeographic province (district of the Transition Forests). This constitutes the southernmost record of the species. An updated description, illustrated with photographs and the characteristics of the enviroment where the species lives are provided. The presence of A. orbygniana in Yungas provides some support the hypothesis of the fragmentation of South American forests by the arid Chacoan diagonal.

Abstract A new species of Asplenium L. (Aspleniaceae) is described and illustrated. Asplenium sylvaticum is endemic of the Yungas and Paraná biogeographic provinces in the Southern Cone. The main diagnostic characters for this taxon are: apical pinnae with one to four caudate lobes at the base, similar in size to lateral pinnae, smooth pinnate blades with 18-36 pairs of caudate pinnae and spores with reticulate perispore, winged folds with scarce equinulaes on the margins and the laesurae wide with smooth margin. The new species belongs to the A. serra species complex group, characterised by xeromorphic habit, creeping rhizome and coriaceous fronds with branched scales on both surfaces, and resembles the other species inhabiting in Argentina, A. achalense and A. serra, in overall leaf architecture and shape but differs of the aforementioned species (and the other species of the A. serra complex) by the unique combination of characters of its rhizomatic scales, fronds and spores. A key with the morphological and palynological characters that differentiate A. sylvaticum from the other taxa belonging to the A. serra complex in the South American Cone and Bolivia is given.

Resumen: La biogeografía reconoce patrones de distribución de los seres vivos en el tiempo y en el espacio, y propone hipótesis acerca de los procesos que causaron dichos patrones. También identifica unidades biogeográficas para proporcionar un sistema jerárquico de regionalización biótica del planeta, delimitando áreas naturales. El objetivo de la presente contribución es presentar la regionalización biogeográfica evolutiva de los Esteros del Iberá, con una puesta al día integrando diversas fuentes de información, describiendo las características fundamentales de la misma, las especies características, los endemismos propios de cada unidad biogeográfica evolutiva, discutiéndose además sus relaciones bióticas y evolución geobiótica. De acuerdo al Código Internacional de Nomenclatura de Áreas (ICAN), se proponen las localidades tipo, con sus respectivas coordenadas geográficas, para la provincia Esteros del Iberá y los distritos Delta del Paraná, Río Uruguay y Sabanas Inundables del Paraná.

RESUMEN Se cita a Didymoglossum krausii (Hymenophyllaceae), Amauropelta jujuyensis y Amauropelta nubicola (Thelypteridaceae) por primera vez para Tucumán, Argentina, en la provincia biogeográfica de las Yungas. Este constituye el registro más austral de los tres taxones. Se proporciona una descripción actualizada, junto con fotografías, y características de los hábitats de las especies en Tucumán.

ABSTRACT Didymoglossum krausii (Hymenophyllaceae), Amauropelta jujuyensis and Amauropelta nubicola (Thelypteridaceae) are recorded for the first time in Tucumán, Argentina, in Yungas biogeographic province. This is the southernmost record of the three taxa. An updated description is provided, along with pictures, and characteristic of the habitats of the species in Tucumán.

Abstract Rumohra aconquijana sp. nov., a restricted endemism of the Montane Jungle district (700-1,500 m asl; Yungas biogeographic province) is reported, described and illustrated. Rumohra aconquijana grows as epiphyte on Ocotea porphyria (Lauraceae) and Sambucus peruviana (Viburnaceae) in humid terraces and slopes of the cloud forest. The new species differs from the widespread R. adiantiformis, especially by the dissection of the laminae, the shape and size of the pinnules. Also, there are differences with all Argentinean and Bolivian and Chilean species of Rumohra in the ornamentation of the perispore, which is folded with few folds, partially fused, narrow and with ridged margins. Here, we present the first species of Rumohra endemic from Argentinean Yungas, as well as a key to identifying the species occurring in Argentina and Bolivia.

Resumo Rumohra aconquijana sp. nov., um endemismo restrito do distrito de Floresta Montana (700-1.500 m asl; província biogeográfica de Yungas) é relatado, descrito e ilustrado. A Rumohra aconquijana cresce como epífita em Ocotea porphyria (Lauraceae) e Sambucus peruviana (Viburnaceae) em locais úmidos e declives de florestas nebulares. A nova espécie difere de R. adiantiformis, especialmente pela dissecação das lâminas, a forma e o tamanho das pínulas. Além disso, difere de todas as espécies argentinas, bolivianas e chilenas de Rumohra na ornamentação do perisporo, que é cristado, parcialmente fusionado, estreito e com margens estriadas. Aqui, apresentamos a primeira espécie endêmica de Rumohra dos Yungas da Argentina, bem como uma chave para identificar as espécies ocorrentes na Argentina e na Bolívia.

Abstract In vitro spore culture and gametophyte characteristics may contribute understanding the life cycle in different fern taxa and also to systematic and taxonomic studies. The family Woodsiaceae contains two genera: Physematium and Woodsia. Physematium montevidensis is the only species recognized for South America, and up to now, no information has been recorded on the gametophytic phase. The aim of this work is to study the development pattern, the morphology and sexual expression of the gametophyte of Physematium montevidensis to provide information about its reproductive biology. The germination pattern was of the Vittaria-type and the gametophyte development of the Aspidium-type. Gametangia appeared 30-40 days after spore germination. Both, cordiform bisexual and spatulate-elongated male gametophytes developed in the cultures. The sporophytes emerged near 3 months after spore sowing. The gametophyte development of Physematium montevidensis and its morphological features are broadly similar to those registered in other taxa of Woodsiaceae.

Resumo O cultivo de esporos in vitro e as características dos gametófitos podem contribuir para a compreensão do ciclo de vida em diferentes táxons de samambaias e também para estudos sistemáticos e taxonômicos. Woodsiaceae contém dois gêneros, Physematium e Woodsia. Physematium montevidensis é a única espécie registrada para a América do Sul. Até o momento, a fase gametofítica desta espécie é desconhecida.. O objetivo deste trabalho é estudar o padrão de desenvolvimento, a morfologia e a expressão sexual do gametófito de Physematium montevidensis para fornecer informações sobre sua biologia reprodutiva. O padrão de germinação foi do tipo-Vittaria e o desenvolvimento do gametófito do tipo- Aspidium. Os gametângios surgiram 30-40 dias após a germinação dos esporos. Ambos, gametófito bisexual-cordiforme e masculino espatulado-alongado se desenvolveram nas culturas. Os esporófitos emergiram em aproximadamente três meses após a semeadura dos esporos. O desenvolvimento do gametófito de Physematium montevidensis e suas características morfológicas são amplamente semelhantes aos registrados em outros táxons de Woodsiaceae.

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.

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.

Abstract We provide a map and shapefile of the 57 biogeographic provinces of the Neotropical region. Recognition of these provinces is based on their endemic species, but their delimitation on the map is based on ecoregions combining climatic, geological, and biotic criteria. These provinces belong to the Antillean, Brazilian and Chacoan subregions, and the Mexican and South American transition zones. We provide a vector file of the biogeographical regionalization by converting the map into a polygon shapefile and a raster file with all provinces.

ABSTRACT As part of floristic surveys in the Southern Cone of South America and the Flora do Brasil 2020 project, we present a revision of Osmundaceae in Brazil. Osmundaceae is represented by two genera (Osmundastrum and Osmunda) and three species. One of them, Osmunda piresii, is endemic to the savannas of Central Brazil, occurring in the states of Goiás, Minas Gerais, and Mato Grosso. Osmunda gracilis is synonymized under Osmunda spectabilis. We present a dichotomous key, descriptions, diagnostic illustrations, distributions, and notes on taxonomy and ecology.

Se presenta un listado de helechos y licofitas del Parque Ferradura, un parque pri- vado ubicado en Canela, Rio Grande do Sul, Brasil. Posee un área de 400ha y pre senta las formaciones boscosas Bosque de Araucaria, el Bosque Mixto Umbrófilo y el Bosque Deciduo Estacional, con lugares de transición y áreas en diverso estado de regeneración. Hemos encontrado 56 especies (cinco licofitas y 51 helechos) en el Parque Ferradura. Las licofitas están representadas por dos familias (Lycopodiaceae y Selaginellaceae) y cuatro géneros, mientras que para helechos se registraron 11 familias y 33 géneros. La mayoría de las especies son exclusivamente terrestres (39 especies). La forma de vida predominante son las hemicriptofitas con crecimiento rosulado (27 especies). Phlegmariurus heterocarpon, Polytaenium lineatum y Vittaria linea ta son consideradas especies raras a nivel local. El área presenta el 15% de la riqueza de especies de licofitas y helechos del estado de Rio Grande do Sul, incluyendo las especies raras, lo que resalta la importancia de la implementación de las necesidades de acciones efectivas para la conservación continua del Parque.

A list of ferns and lycophytes from Ferradura Park, a private park located in Canela, Rio Grande do Sul, Brazil is presented. The park has an area of 400 ha with forest formations such as Araucaria Forest, Mixed Ombrophilous Forest and Seasonal Deciduous Forest, with transition zones and areas at different stages of regeneration. We found 56 species (five lycophytes and 51 ferns) in Ferradura Park. Lycophytes are represented by two families (Lycopodiaceae and Selaginellaceae) and four genera, while 11 families and 33 genera were recorded for ferns. Most of the species are exclusively terrestrial (39 spp.). The predominant life form is hemicriptophytic with rosulate growth (27 spp.). Phlegmariurus heterocarpon, Polytaenium lineatum and Vittaria lineata are considered locally rare. The area presents 15% of the species richness of the State of Rio Grande do Sul including rare species, which highlights the importance of implementing effective actions for the continuing Park conservation.