Lucia Helena Soares-Silva

Arquitectura foliar de las Lauraceae del Distrito Federal, Brasil, y nuevos patrones de venación propuestos

Fueron estudiadas las hojas de 18 especies de Lauraceae que crecen en el Distrito Federal (Brasil), con el objetivo de caracterizar sus patrones de venacion e identificar caracteristicas utiles en su diferenciacion taxonomica, para que junto a su morfologia se puedan obtener criterios utiles que ayuden en su identificacion vegetativa. Las hojas fueron diafanizadas, coloreadas y fotografiadas. Los patrones de venacion del segundo, tercero, cuarto y quinto orden fueron descritos e ilustrados para las especies estudiadas, que presentaron una venacion secundaria de tipo broquidodroma o eucamptodromo-broquidodroma, excepto en Crytocarya aschersoniana y Ocotea aciphylla con venacion broquidodroma prominula reticulada. La densidad de areolas se mostro como un buen caracter taxonomico, lo que no ocurrio con el numero de lados que estas poseen. Fueron propuestos los conceptos de nudos y ramas de las venulas y criterios para la clasificacion de sus ramificaciones. La mayoria de las especies poseen venulas ramificadas. Los caracteres analizados, unidos con los morfologicos tales como tipo de indumento, formas de borde, y presencia y/o ausencia de domacios, posibilitaron la diferenciacion de las 18 especies estudiadas, evidenciando la clara importancia de la arquitectura foliar en el reconocimiento taxonomico de especimenes en estado vegetativo.

Leaf epidermal descriptors applied to the taxonomy of Lauraceae, including new anatomical characters

The difficulty of identifying Lauraceae species is well known. The leaf epidermis of 18 species from the Federal District, Brazil, was analyzed to test more characters as an aid to the taxonomy of this family. New anatomical characters are proposed here, such as sinus number, internal angles and number of sides of the common epidermal cells, their arrangement around the trichome base, and the shape and width of the subsidiary cells in relation to the guard cells. Epidermal characters that can aid in the identification of the studied species are: the contour of the common cells on both leaf surfaces and their anticlinal wall width, number of sides of the polygonal cells, sinus number, presence of angles greater than 180°, presence and type of indumentum, common cells with radial arrangement around the trichome base, stomatal position relative to the rest of the epidermis and width of the subsidiary cells in relation to the guard cells. Glabrous and glabrescent leaves are distinguished. Two species have unique characters: Aniba heringeri , with papillae on the abaxial surface, and Cryptocarya moschata , with peculiar horseshoe-shaped subsidiary cells. Characters of the epidermis together with the external leaf morphology are sufficient to distinguish the studied species. Additionally, we report for the first time the occurrence of Mezilaurus crassiramea and Ocotea diospyrifolia for the flora of Federal District, Brazil.

Two new records for Bromeliaceae in the central-west region of Brazil: Vriesea friburgensis and Tillandsia polystachia

This study presents the first records of Vriesea friburgensis and Tillandsia polystachia for the central-west region of Brazil. The two species were found in gallery forests of the National Forest of Brasilia, Distrito Federal. This conservation unit is located in the core region of the Cerrado domain. This finding extends the number of species of flora of this locality and of the Central-west Region, and also increases the area of distribution of the two species, previously restricted to the northeast, southeast and south of Brazil.

Floristic survey of the herbaceous-shrub layer of a gallery forest in Alto Paraíso de Goiás - GO, Brazil

Flowering species of the herbaceous and shrubby lay er were sampled in a gallery forest at Portal da Ch apada, Alto Paraiso de Goias-GO in the Chapada dos Veadeiros du ring 12 months growing within 4.5 meters on either side of a raised pathway 2.4 Km long. The collections were in cluded to University of Brasilia Herbarium (UB). A total of 138 species (103 genera and 40 families) were recorded; the most species-rich families were Asteraceae (22 ), Poaceae (14), Rubiaceae (12), Fabaceae (11) and Melastomata ceae (7). The richest family in number of genera wa s Asteraceae (19), followed by Poaceae (8), Fabaceae (8) and Rubiaceae (7). The results showed a meaning ful increase in the Chapada dos Veadeiros flora, especi ally considering the herbaceous-shrubby layer of th e gallery forests (223.6%). Despite the richness of the flor a, the number of endemics species in the Goias Stat e was only 1.5%.