FLORISTIC COMPOSITION AND PHYTOSOCIOLOGIC AL STRUCTURE IN A RIPARIAN FOREST OF TIBAGI RIVER, TELEMACO-BORBA, PARANA, BRAZIL

The floristic composition and phytosociological structure of a riparia n forest along the Tibagi river in the county of Tibagi Parana state, Southern Brazil (24 degrees 20' S, 50 degrees 37' W) were analysed. Th e quadrat method was used to sample all woody vegetation with a diamet er of breast height greater than or equal to to 5 cm in one hectare of a hundred contiguos 100 m(2) quadrats. A total of 1126 individuals, 1 09 species, 75 genera and 38 families were recorded, and the Shannon-W eaver index was H' = 3,61. The most important species were Actinostemo n concolor, Inga marginata, Nectandra megapotamica, Urera baccifera, C ampomanesia xanthocarpa, Cabralea canjerana, Lonchocarpus guilleminian us, Aspidosperma polyneuron and Sorocea bonplandii, and the families t hat presented the greatest numbers of species were Myrtaceae (13 spp), Lauraceae (10 spp), Meliaceae (9 spp), Fabaceae (7 spp), Mimosaceae ( 6 spp) and Euphorbiaceae (5 spp). These results sugest that this comun ity is conserved in terms of floristic diversity and phytosociological structure, and the occurence of some species in associations with env iromental proprieties indicates different mature succecional degrees i n the forest.