Abstract The Yabotí Biosphere Reserve (Prov. Misiones, Argentina) with 221,155 ha, represents one of the southernmost relicts of the Paranaense forest. Currently, a project is being developed in the area to inventory and describe the ferns and lycophytes. As a result of these studies, we identify a new species of Amauropelta, A. yabotiensis. Within this genus, it belongs to the group of species with uncinate hairs and presents a unique combination of diagnostic features, including the type of pubescence on the rhizome scales, the shape of the fronds and segments and type of venation. Here, we described and illustrated the species and we analyzed its taxonomic affinities and geographic distribution. Additionally, we provided a distribution map and a key to distinguish it from other Amauropelta species from Misiones province. With this new finding, we highlighted the importance of the Yabotí Reserve as a reservoir of biodiversity in the region.

Abstract Hypolepis ×paulistana was described in 2016 as a putative hybrid, known from a single gathering. The hybrid status of these plants was based solely on the intermediate morphology of the sporophyte, when compared to its presumed parent species. These were thought to be H. stolonifera and H. rugosula, but, H. rigescens (Kunze) T. Moore could not be explicitly ruled out either. In the present work, we tested the hybrid status of Hypolepis ×paulistana adding palynological evidence and by using chloroplast sequences to unambiguously identify the maternal progenitor of the species. We find that sporangia of Hypolepis ×paulistana contain both well-formed spores, as well as spores with morphological and developmental anomalies. The size of the regular spores and the abnormal spores suggest that H. ×paulistana is likely a diploid, and probably infertile hybrid. The ornamentation of the regular spores of H. ×paulistana is similar to that of H. stolonifera. The chloroplast sequences of H. ×paulistana are identical to those of H. stolonifera, as well as their sister position within the global phylogeny of the genus. Thus, we provide new evidence for the hybrid status of H. ×paulistana, and we corroborate the earlier finding that H. stolonifera is the maternal parent.

Abstract Marquez, G. J.; A. Yañez & D. Ocampo Terraza. 2020. First record of Megalastrum oreocharis (Dryopteridaceae) for Argentina. Darwiniana, nueva serie 8(1): 389-394. Megalastrum oreocharis is cited in Argentina for the first time. Within Megalastrum, this species differs from the others in Misiones province, for the presence of rachis, costae and veins hairs greater than 0.5 mm and echinate spores. The careful study of microcharacters within the genus Megalastrum has become an important tool to find records of new species in Argentina, which contributes to ongoing biological diversity studies.

Resumen Marquez, G. J.; A. Yañez & D. Ocampo Terraza. 2020. Primer registro de Megalastrum oreocharis (Dryopteridaceae) para Argentina. Darwiniana, nueva serie 8(1): 389-394. En el presente trabajo se cita por primera vez en Argentina a Megalastrum oreocharis. Dentro de Megalastrum, esta especie se diferencia de otras por la presencia de pelos mayores a 0,5 mm en el raquis, costas y venas, y esporas equinadas. El estudio minucioso de los microcaracteres dentro del género se ha transformado en una herramienta importante para confirmar el hallazgo de nuevos registros para Argentina, lo que enriquece los proyectos de diversidad biológica en curso.

Abstract Abstract The Parque Provincial Moconá is in the east of the Misiones province, surrounded by Yabotí and Uruguay rivers. It belongs to Yabotí Biosphere Reserve, and together with other Biosphere’s protected areas, it represents one of the main relicts of the Paranaense forest in the country. In this work, fern and lycophyte species that grow in the park were exhaustively surveyed. Field trips were carried out to the study area and national herbaria were consulted. Seventy-one taxa were found, 38 of which represent new records for the protected area. A comprehensive key to the species and habitat considerations are provided. Additionally, the relationship with the adjacent protected area Parque Estadual do Turvo, Rio Grande do Sul (Brazil) and the relevance to the conservation of native flora is discussed.

Resumen São apresentados os resultados do levantamento florístico das angiospermas da APA Municipal do Rio Vermelho/Humboldt, localizada em área de Mata Atlântica no sul do Brasil. As coletas foram realizadas entre os anos de 2004 e 2017, e a identificação das espécies foi baseada em consulta bibliográfica, comparação com acervos de herbários e auxílio de outros especialistas. Foram inventariadas 979 espécies, distribuídas em 134 famílias, com maior riqueza de Asteraceae (87 espécies), Orchidaceae (86), Solanaceae (58), Melastomataceae (51), Bromeliaceae, Fabaceae, Rubiaceae (cada uma com 37), Myrtaceae (34), Piperaceae (33), Cyperaceae e Poaceae (ambas com 18). Doze espécies estão classificadas como ameaçadas de extinção e 21 espécies são novas ocorrências para o estado de Santa Catarina. A elevada riqueza florística demonstra a importância da APA para a conservação da diversidade vegetal no sul do Brasil.

First record of the genus Actinostachys (Schizaeaceae) for Argentina. The fern Actinostachys pennula (Schizaeaceae) is cited for the first time from Argentina, on the basis of material recently collected in the northeast of Misiones province. It is provided a description of the species, ecological observations, and ÍNustrations of sporophyte and spores.

Se registra por primera vez para la flora Argentina el helecho Actinostachys pennula (Schizaeaceae), sobre la base de material recién recolectado en el nordeste de la provincia de Misiones. Se incluye una descripción de la especie, observaciones ecológicas, e ilustraciones del esporofita y esporas características de la especie.

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.

Wind pollination in Asteraceae is well documented only in few tribes. Particularly, in Eupatorieae, apparent anemophily has only been reported in 10 species belonging to the genera Critonia, Decachaeta, Eupatorium, Koanophyllon, and Neohintonia, most of which inhabit North and Central America, with only two species from South America. The genus Acanthostyles has only one species, Acanthostyles buniifolius, which is widely distributed in southern South America. This species shows features that may suggest a pollination mechanism mediated by wind. We analyzed in detail some morphological and palynological traits related to the anemophilous syndrome. As a result, we identified some characters of A. buniifolius associated to wind pollination: presence of loose and pendulous secondary inflorescence with mainly downward oriented small heads, increased of proportion of stigmatic area in relation to the total length of the style branch, acicular style sweeping laxly arranged and wide-caveate, microechinate (= subechinate) pollen. This paper proposes first evidence of possible anemophily for a species of subtribe Dysinaphiinae within the Eupatorieae tribe.

La polinización por el viento en la familia Asteraceae se encuentra documentada en unas pocas tribus. Particularmente en Eupatorieae, sólo se ha reportado aparente anemofilia en 10 especies pertenecientes a los géneros Critonia, Decachaeta, Eupatorium, Koanophyllon y Neohintonia, la mayoría de las cuales crece en América del Norte y Central, con sólo dos especies que alcanzan América del sur. El género Acanthostyles incluye una única especie, Acanthostyles buniifolius, la cual se encuentra ampliamente distribuida en el sur de América del Sur. Esta especie presenta características que sugieren un mecanismo de polinización mediado por el viento. Analizamos en detalle algunos caracteres morfológicos y palinológicos relacionados con el síndrome anemófilo. Como resultado, identificamos algunos atributos asociados con la polinización por el viento: inflorescencia laxa y péndula con capítulos pequeños orientados principalmente hacia abajo, estilo con mayor proporción de área estigmática en relación al largo total de la rama del estilo, pelos barredores del estilo aciculares dispuestos laxamente y polen con amplio cavus, microequinado (=subequinado). Este trabajo aporta las primeras evidencias de la posible anemofilia para una especie de la subtribu Dysinaphiinae, dentro de la tribu Eupatorieae.

A morfologia dos esporos e a ultraestrutura da parede do Microlepia speluncae e Pteridium arachnoideum da Província Paranaense foram analisadas com LM, SEM e TEM e uma análise comparativa foi realizada. Em am bas as espécies, os esporos são cobertos por uma rede tridimensional de cordões ramificados e fundidos, dis postos tangencialmente à superfície, e alguns fios com extremidades livres também são vistos. As espécies foram diferenciadas pela morfologia e a frequência de fusão de fios e redes de distribuição sobre a superfície dos esporos. Em ambas as espécies a exospore é de duas camadas na seção, ambas as camadas são atravessadas por canais únicos ou ramificados. O perisporo é de três camadas na seção: a camada interna é aderida à exospore, a camada do meio é formada por uma rede tridimensional de cordões e a camada exterior é descontínua. A ultraestrutura do perisporo de Microlepia speluncae foi interpretada como formada por subunidades helicoidais exibidas em torno de um canal central. A morfologia dos esporos e ultraestrutura do perisporo permitem diferenciar Microlepia de Pteridium, mas também para os outros gêneros Dennstaedtiaceae que crescem na Província Paranaense. Os resultados obtidos permitem estabelecer relações que nos permitem reconhecer diferentes grupos e nos deu uma nova referência para obter um melhor conhecimento da família.

The spore morphology and wall ultrastructure of Microlepia speluncae and Pteridium arachnoideum from the Paranaense Province were analyzed with LM, SEM and TEM and a comparative analysis was carried out. In both species the spores are covered by a three-dimensional network of threads branched and fused, tangentially arranged to the surface, and some free-end threads are also seen. The species were differentiated by morphology and the frequency of threads fusion and the networks distribution on the surface of the spores. In both species the exospore is two-layered in section, both layers are traversed by single or branched channels. The perispore is three-layered in section: the inner layer is adhered to the exospore, the middle layer is formed of a three-dimensional network of threads and the outer layer is discontinuous. The perispore ultrastructure of Microlepia speluncae was interpreted as formed of helical subunits displayed around a central channel. The spore morphology and perispore ultrastructure allow differentiating Microlepia from Pteridium but also to the other Dennstaedtiaceae genera that grow in the Paranaense Province. The results obtained allow establishing relationships that let us recognize different groups and gave a new reference to get a better knowledge of the family.

Dennstaedtia dissecta is recorded for the first time for the Argentinean flora in the Misiones Province. This new record was discovered during the study of herbarium specimens from BA and LP, and then corroborated with field collections from Cruce Caballero Provincial Park and Urugua-í Provincial Park. In addition to the characteristics of rhizome and lamina, the spores were an important information source for the identification of this species. The diagnostic characters are described and illustrated, including a key to identify the species of Dennstaedtia from Misiones.

Se cita por primera vez para la flora argentina a Dennstaedtia dissecta, hallada en la provincia de Misiones. Este nuevo registro surgió del estudio de ejemplares de los herbarios BA y LP, y luego se corroboró con colecciones realizadas en los Parques Provinciales Cruce Caballero y Urugua-í. Además de las características del rizoma y la lámina, las esporas resultaron una importante fuente de información en la identificación de esta especie. Se describen e ilustran los caracteres diagnósticos, y se incluye una clave para identificar a las especies de Dennstaedtia presentes en Misiones.

The family Cyatheaceae comprises about 500 species of tree ferns. Their distribution is pantropical and in Argentina is represented by four species, grouped in genera Alsophila y Cyathea: A. setosa, A. odonelliana, C. atrovirens and C. delgadii. In this paper, an update of the available information of the mentioned species is presented. A key to diferentiate the species growing in Argentina, their descriptions and a distribution map are also given. Spores are ridged in Alsophila and with rodlets in Cyathea. Indusia and scales of petiole basis are also illustrated.

La familia Cyatheaceae comprende alrededor de 500 especies de helechos arborescentes. Su distribución es pantropical y en Argentina se encuentra representada por 4 especies, reunidas en los géneros Alsophila y Cyathea: A. setosa, A. odonelliana, C. atrovirens y C. delgadii. En este trabajo se presenta una actualización de la información disponible hasta el momento referente a estas especies. Se exponen microfotografías de las esporas, que presentan la superficie con lomos en Alsophila y con cordones en Cyathea. Se ilustran los indusios y escamas de la base de los pecíolos, que son de importancia fundamental para la diferenciación de las especies estudiadas. Asimismo se presenta un mapa de distribución y una clave de las especies que crecen en Argentina.

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.

Vittaria graminifolia is recorded for the first time for Corrientes and Misiones, Argentina. A key to differentiate the two species of Vittaria in Argentina is given, and V. graminifolia is illustrated and described. Argyrochosma nivea var. flava, known for NW and Central Argentina, is recorded for the first time for the NE. The distribution and ecology of these species are discussed.

Se cita por primera vez para Argentina a Vittaria graminifolia (Vittariaceae) coleccionada en las provincias de Corrientes y Misiones. Se aporta una clave para diferenciar las dos especies de Vittaria presentes en el país, y se ilustra y describe V. graminifolia. Argyrochosma nivea var. flava (Pteridaceae), conocida para el NO y centro argentino, se registra por primera vez para el NE. Se brindan comentarios sobre la distribución y ecología de las especies mencionadas.

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.