Comparative palynological analysis of <italic>Lygodium venustum</italic> Sw. and <italic>L. volubile</italic> Sw. (Lygodiaceae)

<p id="para1">The genus <italic>Lygodium</italic> Sw. is one of the few climbing ferns in the world. The spores of <italic>L. venustum</italic> Sw. and <italic>L. volubile</italic> 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 &#181;m, and the polar diameter is 64-84 &#181;m. The ornamentation in <italic>L. venustum</italic> is verrucate-tuberculate while in <italic>L. volubile</italic>, 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 <italic>L. venustum</italic>, it is smooth in contrast with the ornamented exospore of <italic>L. volubile</italic>. 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.</p><br><p id="para2">O g&#234;nero <italic>Lygodium</italic> Sw. &#233; um das poucas samambaias trepadoras no mundo. Os esporos de <italic>L. venustum</italic> Sw. e <italic>L. volubile</italic> Sw. foi estudados com microscopias de luz e eletr&#244;nicas de transmiss&#227;o e varredura. Este trabalho &#233; baseado em material de herb&#225;rio. Os esporos s&#227;o trilete, triangular com lados retos para convexo em vista polar. O equatorial di&#226;metro &#233; 72-104 &#181;m e o di&#226;metro polar &#233; 64-84 &#181;m. O ornamenta&#231;&#227;o em <italic>L. venustum</italic> &#233; verrucose-tuberculoso enquanto em <italic>L. volubile</italic> &#233; verrucose-tuberculoso no proximal cara e com poucos cume no distal cara, em que um micro-ornamenta&#231;&#227;o constitu&#237;da por verrugas e tub&#233;rculos &#233; observado. Um cume equatorial tamb&#233;m est&#225; presente. O exosporo &#233; de dois camadas, em <italic>L. venustum</italic> &#233; liso em contraste com o exosporo ornamentado de <italic>L. volubile</italic>. O perisporo &#233; similar nas duas esp&#233;cies analisadas. Esta parede &#233; de quatro camadas com elementos particulares dispostas radialmente na camada do meio. Nas superf&#237;cies de esporos de ambas esp&#233;cies poucos spheroids &#233; observado. Os resultados apresentados no presente estudo podem ser &#250;til para o sistem&#225;tica do g&#234;nero bem como para prop&#243;sitos filogeneticos.</p

Comparative palynological analysis of Lygodium venustum Sw. and L. volubile Sw. (Lygodiaceae)

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 &#181;m, and the polar diameter is 64-84 &#181;m. 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

Diversidad de helechos y licofitas del Parque Nacional Lago Puelo (Chubut-Argentina) Diversity of ferns and licophytes of the National Park Lago Puelo (Chubut- Argentina)

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.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