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.

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.

The spores of Schizaea fistulosa from Chile were studied using light microscopy (LM), scanning (SEM) and transmission electron microscopy (TEM). The spores are monolete and elliptic in polar view. The major equatorial diameter is 71-85 µm and the polar diameter is 54-61 µm. The laesurae are 50-60 µm long and, in some cases, bifurcated. The sporoderm ultrastructure is first mentioned and described here. The exospore is two-layered in section, verrucate-tuberculate with single or fused elements forming short ridges. The perispore is single-layered, 10-30 nm thick and it is only visible under transmission electron microscopy. On the spore surface, numerous, single or fused, spheroids and nanospheroids of different sizes were observed attached to the perispore surface. The results are discussed and compared with previous studies in Schizaea.

Se estudiaron las esporas de Schizaea fistulosa de Chile con microscopía óptica (MO), electrónica de barrido (MEB) y transmisión (MET). Las esporas son monoletes y elípticas en vista polar. El diámetro ecuatorial mayor es de 71-85 µm y el diámetro polar de 54-61 µm. Las lesuras son de 50-60 µm de longitud y en algunos casos están bifurcadas. La ultraestructura de la esporodermis se describe por primera vez. El exosporio en sección posee dos capas y es verrucoso-tuberculado con elementos aislados o fusionados formando lomos cortos. El perisporio posee una sola capa, de 10-30 nm de espesor y solamente es visible con microscopía electrónica de transmisión. Sobre la superficie de la espora, se observan numerosos esferoides y nanoesferoides de diferentes tamaños, adheridos a la superficie. Se discuten los resultados y se los compara con estudios previos en Schizaea.

The family Equisetaceae is represented in the study area by the genus Equisetum with two species, E. bogotense and E. giganteum. The study was based on herbarium and fresh specimens and the spores were studied under light microscope, scanning and transmission electron microscopes. The spores are spheroid, 35-64 μm in equatorial diameter, the cytoplasm has chlorophyll. In both species studied, the spores have a circular and small unique type of aperture which at both sides of the aperture, in the outer side have two thread-like elaters, spathulate. These structures are non-resistant to the acetolysis treatment. The sporoderm is composed of two walls, perispore, 930 nm-1,2 μm thick, ornamented, with two layers in section. The exospore is two layered, compact, 1,4-3,1 μm thick, slightly wave-like. Between both walls was observed an intermediate layer composed of a laxe structure, in spores in different stages of maturation. In both species, the spores are similar in the shape and sporoderm ultrastructure while differences were found in spore sizes.

La familia Equisetaceae se haya representada en el Noroeste de Argentina por el género Equisetum Michx. ex DC con dos especies, E. bogotense Kunth y E. giganteum L. El estudio se realizó en base a material de herbario y fresco. Las observaciones se realizaron con microscopios óptico y electrónicos de barrido y transmisión. Las esporas son esferoidales, miden 35-64 μm de diámetro ecuatorial, su citoplasma posee clorofila. En ambas especies, las esporas presentan una estructura abertural circular y a ambos lados de la misma poseen un par de eláteres acintados de extremos espatulados, no resistentes al tratamiento de acetólisis. La esporodermis consta de dos paredes, perisporio, delgado, ornamentado, con dos estratos, de 930 nm-1,2 μm de espesor, y exosporio, de 1,4- 3,1 μm de espesor, compacto, con dos estratos y superficie levemente ondulada o plegada. Entre ambas paredes se ha observado una capa intermedia de naturaleza laxa, y diferente espesor en esporas con distintos estadios de maduración. Las esporas son similares, en ambas especies, en cuanto a la forma y ultraestructura de la esporodermis; se observan diferencias en el tamaño de las mismas.

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.

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.

Based on the aeromycological analysis of La Plata city, artificial Morphological Groups of fungal spores were defined. This study is a methodological contribution to the identification and counting of a fraction of the atmospheric micobiota. For the definition of groups, the criteria of Saccardo (1886) were taken into account and the groupings created by Díaz et al. (1998) and Aira et al. (2005) have been reformulated. Four new groups have been created and other sporal types have been incorporated to previous classifications. Each of them includes 2 to 6 spore types belonging to the Phylum Zygomycota, Basidiomycota and Ascomycota and their anamorphs, assigned to generic level. Characters that define such associations are: Absidia Group, hyaline amerospores; Cortinarius Group, pigmented amerospores; Didymella Group, hyalines or slightly colored didymospores; Didymosphaeria Group, pigmented didymospores and didymoconidia; Leptosphaeria Group, hyaline to pigmented phragmospores and Helminthosporium Group, hyaline to pigmented distoseptated phragmoconidia. The aim of this work is to give a tool to facilitate the task of data processing by providing new qualitative elements to prior classifications and contributing to the complex problem of identification of fungal spores presents in atmosphere.

A partir del análisis del registro aeromicológico de la ciudad de La Plata se propone la definición de Grupos Morfológicos de esporas del Reino Fungi. Este estudio constituye un aporte metodológico a la identificación y recuento de una fracción de la micobiota atmosférica. Para la definición de los grupos, se han tenido en cuenta los criterios de Saccardo (1886) y reformulado los agrupamientos de Díaz et al. (1998) y Aira et al. (2005). Se han creando 4 nuevos grupos y se han incorporando otros tipos esporales a las clasificaciones previas. Cada grupo, incluye entre 2 y 6 tipos de esporas pertenecientes a los Phylum Zygomycota, Basidiomycota y Ascomycota y sus anamorfos, que han sido asignados a nivel genérico. Los caracteres que definen dichas asociaciones son: Grupo Absidia, amerosporas hialinas; Grupo Cortinarius, amerosporas pigmentadas amigdaliformes; Grupo Didymella, didimosporas hialinas o levemente coloreadas; Grupo Didymosphaeria, didimosporas y didimoconidios pigmentados; Grupo Lepthosphaeria, fragmosporas septadas hialinas a pigmentadas y Grupo Helminthosporium, fragmosporas distoseptadas hialinas a pigmentadas. Esta investigación aspira a proporcionar una herramienta que facilite el procesamiento de datos y aporte nuevos elementos cualitativos a las clasificaciones previas, contribuyendo en la compleja problemática de identificación de las esporas fúngicas.

A morfologia e a ultraestrutura da parede de megasporos e microspores de Isoetes sehnemii que crescem no Brasil foram analisados como parte do estudo de Isoetaceae presente no sul da América do Sul. As observações foram realizadas com microscopias de luz e eletrônicas de transmissão e varredura. Os megasporos são triletes com 350-450μm de diâmetro equatorial. A superfície é reticulada. Em secção o esporoderma possui 100μm de espessura incluindo ornamentação. A parede é composta de um perisporo silicoso que consiste de elementos fusionados curtos e achatados formando uma rede tridimensional. O exosporo tem duas zonas com diferentes estruturas. O endosporo é fibrilar. Os microsporos são monoletes, 21-27μm de diâmetro equatorial. A esporoderme é composta por um perisporo esporopolínico rugulado. Um espaço entre o para-exosporo e o exosporo é evidente. O exosporo é compacto. O endosporo é fibrilar. A análise ultraestrutural torna evidente homologias relativas a estrutura e organização das camadas abaixo do perisporo em ambos os tipos de esporos. Uma possível similaridade e estabilidade na ultraestrutura do presente esporo e fósseis pode também ser inferida. Além disso, haveria uma correlação entre o habitat da planta, a ornamentação do esporo e a distribuição geográfica.

The morphology and wall ultrastructure of megaspores and microspores of Isoetes sehnemii that grows in Brazil were analyzed as part of the study of the Isoetaceae present in Southern South America. The observations were performed with light, scanning and transmission electron microscopes. The megaspores are trilete, 350-450μm in equatorial diameter. The surface is reticulate. In section, the sporoderm is 100μm thick including the ornamentation. The wall is composed of a siliceous perispore, which consists of short fused flatten, elements forming a three-dimensional mesh. The exospore has two zones of different structure. The endospore is fibrillar. The microspores are monolete, 21-27μm in equatorial diameter. The sporoderm is composed of a sporopollinic rugulate perispore. A space between the paraexospore and the exospore is evident. The exospore is compact. The endospore is fibrillar. The ultrastructural analysis akes hoologies evident concerning structure and organization of the layers belo the perispore in both spore types. A possible similarity and stability in the ultrustructure of the present spores and fossils could be also inferred. In addition, there would be a correlation among the plant habitat, the spore ornamentation and the geographic distribution.

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.