Checklist and geographic distribution of Myrtaceae species occurring in campinaranas of the Brazilian Amazon

Abstract

White-sand vegetation (campinarana) is a type of vegetation restricted to oligotrophic and highly leached white sand soils in the Amazon phytogeographic domain that includes grassland to forest phytophysiognomies. Campinaranas cover about 5% of this phytogeographic domain and are impacted by various anthropic activities that put plant species, especially endemic ones, at risk. Myrtaceae has significant representativeness in oligotrophic edaphic environments, but floristic and taxonomic studies on the family in campinaranas are still few and geographically limited. We present a checklist of Myrtaceae species known from campinaranas of the Brazilian Amazon based on the survey of herbarium specimens and literature data in order to assess the level of endemism of these species for this vegetation type. We compiled occurrence records of 72 species and six genera. Myrcia and Eugenia were the genera with the highest number of species. Overall, 38 species (53%) occurred only in the Amazon and two were endemic to campinaranas (Eugenia campina and Myrcia psammophila). Four species are new records for the Brazilian Amazon: Blepharocalyx salicifolius, Eugenia hatschbachii, Myrcia anceps and Myrcia racemosa. The specific richness of Myrtaceae in Brazilian campinaranas is likely to be underestimated since extensive areas, especially those farther from the riverbanks, in the states of Amazonas and Roraima, have not yet been intensively surveyed.