Vanilla lindmaniana and V. palmarum (Orchidaceae) are distinct allopatric species

Background and aims – With more than 40 species, Brazil is the centre of diversity for Vanilla . Despite the species richness, few studies on species boundaries involving Brazilian taxa have been carried out. Consequently, many species have been synonymized under taxa with a wider distribution. This is the case for V. lindmaniana , a species currently synonymized under V. palmarum . While studying the diversity of Brazilian Vanilla , differences between plants from the Amazonia/Cerrado/Pantanal and Caatinga/Atlantic Forest Biomes were recorded. Material and methods – Detailed descriptions based on herbaria specimens and living material of V. lindmaniana and V. palmarum are provided and a morphological comparison is given. Illustrations of both species based on living plants is provided, and their geographic distributions are presented. Key results – Plants occurring in the Amazon, Cerrado, and Pantanal Biomes correspond to V. lindmaniana , while V. palmarum occurs in the Caatinga and Atlantic Forest Biomes. Vanilla lindmaniana is distinguished from V. palmarum by several vegetative and reproductive characteristics, such as the size of leaves and flower structures, and the shape of the fruits. Characteristics associated to pollination strongly differ between both taxa. Vanilla lindmaniana is ornithophilous, while the labellar morphology of V. palmarum suggests pollination by bees. Both species occur as epiphytes on palms: Vanilla lindmaniana predominantly on Acrocomia , Attalea , and Mauritia , while V. palmarum on Elaeis and Syagrus . Both V. lindmaniana and V. palmarum are assessed as Endangered. Conclusion – Appraisal of reproductive and vegetative characteristics from living specimens is crucial in delimitating species boundaries in Vanilla . Species delimitation based on ecological divergencies, plus geographic disjunctions have advanced the current evaluation and understanding of diversity in this economically and ecologically important orchid genus. All evidence reveals that V. lindmaniana is distinct from V. palmarum . Vanilla palmarum is endemic to Brazil, while V. lindmaniana is widely distributed throughout South America.