Descrição e discriminação de formas de nervuras foliares utilizando a representação polinomial cúbica de Hermite

This paper describes a method for leaf vein shape characterization using Hermite polynomial cubic representation. The elements associated with this representation are used as secondary vein descriptors and their discriminatory potential are analyzed based on the identification of two legume species (Lonchocarpus muehlbergianus Hassl. and L. subglaucescens Mart, ex Benth.). The elements of Hermite geometry influence a curve along all its extension allowing a global description of the secondary vein course by a descriptor of low dimensionality. The obtained results shown the analyzed species can be discriminated by this method and it can be used in addition to commonly considered elements in the taxonomic process.

Abundância de ramos reprodutivos e produção de sementes em populações de Ipomoea pes-caprae (L.) R. Br. na Ilha de Santa Catarina, Brasil

The variation in the proportion of reproductive branches, fruit, and seed production of Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) were evaluated at ten beaches on Santa Catarina Island, state of Santa Catarina, Brazil. Three patches per beach of Ipomoea pes-caprae were monitored, involving two reproductive cycles. Ipomoea pes-caprae presented initially an average length of patches of 14 m, with 9.6 branches/m² and 39% of reproductive branches. The proportion of reproductive branches varied between the cycles, but there was not noticed an alternation of reproductive effort between the subsequent cycles. There was a reduction in the percentage of reproductive branches at six localities. In four beaches where Ipomoea pes-caprae populations declined, occurred reduction in the reproductive vigor, and in the seed production, being these declines associated to strong sea erosion. In another hand, in one beach with population increase, there were little reproductive branches due to the occurrence of young stolons. Four patches never maturated fruits, being three of these located at small beaches. The fruit and seed productions in the patches showed values up to 40 fruits/m² and up to 140 seeds/m², respectively. Populations with great seed production were localized in areas adjacent to great coastal plains, which may represent potential seed sources for areas with small seed production in the island.

Taxonomic value of foliar characters in Dahlstedtia Malme: Leguminosae, Papilionoideae, Millettieae

Dahlstedtia Malme (Leguminosae) is a neotropical genus, native to the Brazilian Atlantic Forest, and comprises two species, D. pinnata (Benth.) Malme and D. pentaphylla (Taub.) Burk., although it has been considered a monotypic genus by some authors. Leaf anatomy was compared to verify the presence of anatomical characters to help delimit species. Foliar primordium, leaflet, petiolule, petiole and pulvinus were collected from cultivated plants (Campinas, SP, Brazil) and from natural populations (Picinguaba, Ubatuba and Caraguatatuba, SP, Brazil - D. pinnata; Antonina, PR, Brazil - D. pentaphylla). Studies on leaflet surface assessment (Scanning Electron Microscopy), as well as histology and venation analyses were carried out of dehydrated, fresh and fixed material from two species. Leaflet material was macerated for stomatal counts. Histological sections, obtained by free-hand cut or microtome, were stained with Toluidine Blue, Safranin/Alcian Blue, Ferric Chloride, Acid Phloroglucin. Secretory cavities are present in the lamina, petiolule, petiole, pulvinus and leaf primordium in D. pentaphylla, but not in D. pinnata, and can be considered an important character for species diagnosis. Other leaf characters were uninformative in delimiting Dahlstedtia species. There is cambial activity in the petiolule, petiole and pulvinus. This study, associated with other available data, supports the recognition of two species in Dahlstedtia.