Levantamento florístico e potencial ornamental de plantas da restinga do Rio Grande do Norte, Brasil: subsídios para um paisagismo sustentável

Abstract

The dissertation includes the floristic survey of vascular plants in fragments of restinga of the Bonfim-Guarairas Environmental Protection Area, in the state of Rio Grande do Norte, Brazil, as well as the analysis and indication of native plants with ornamental potential and possibilities of its use in landscape projects. Initially, we present a general characterization of the Brazilian „restingas‟, the objectives and justification of the dissertation, which is structured in chapters. The chapter I provide a floristic survey of vascular plants occurring in Bonfim-Guarairas Environmental Protection Area, based on field collections, herbarium and bibliography. The results of this chapter include the recognition of 58 families, 131 genera and 169 species of which 23 are new occurrences for Rio Grande do Norte. The angiosperms were responsible for 166 species (98.2% of total), 125 genera (97.6%) and 55 families (94.8%) and three families (5.1%) were composed of monilophytes. Cyperaceae (11.8% of species), Poaceae (10.6%), Fabaceae (8.8%), Rubiaceae and Orchidaceae (4.7%) were the richest families in number of species. Also, the occurrence of the Orobanchaceae represented by Agalinis hispidula and Buchnera palustris is the first record for the family in the Rio Grande do Norte flora‟s. A broad distribution pattern was confirmed for most species, which also occur in adjacent biogeographic provinces, reinforcing the mixed origin of restinga flora. Aditionally, we found a predominantly autochoric dispersion pattern, followed by zoocoric. In chapter II we discuss the ornamental potential of native plants from restinga of Rio Grande do Norte, based on the analysis of their aesthetic characteristics. A list of plants with their scientific name family, habit, aesthetic characteristics, and possible use in landscaping is provided. The results show a total of 25 species grouped in 22 genera and 16 families with ornamental potential. Convolvulaceae (3 spp.), Apocynaceae, Araceae, Cactaceae, Chrysobalanaceae and Rubiaceae (2 each) are highlighted for their aesthetic characteristics. Most of the species (17; 81%) are endemic to Brazil and two (Aspilia procumbens and Melocactus violaceus) are endangered. In chapter III we present and discuss the ornamental potential of the genus Justicia (Acanthaceae) for the Paraíba flora. Dichotomous key for identification of species found in that state, in addition to a new occurrence, Justicia thunbergioides, followed by taxonomic commentaries, are also presented.