Philodendron luisae (Araceae), a new species from Rio de Janeiro State, Brazil

BACKGROUND: Philodendron is the second largest genus of Araceae, being highly diverse in the Atlantic Forest biome, with nearly one third of the Brazilian species occurring in Southern Brazil, particularly in Rio de Janeiro state. During a local inventory in Silva Jardim municipality, we found a peculiar population of Philodendron growing in lowland rainforest. RESULTS: After morphological analysis and comparisons with similar species, the population proved to be a new undescribed species of subgenus Philodendron section Macrobelium. CONCLUSIONS: The new species, named Philodendron luisae, is here described, illustrated and compared to morphologically close species.