Descriptions and phylogenetic relationships of four new species and a new name of Habenaria (Orchidaceae) from the cerrado and campos rupestres of Brazil

Abstract

Four new orchid species and one variety from the cerrado and campos rupestres of central and south-eastern Brazil are described and illustrated: Habenaria brachydactyla, H. irwiniana, H. minuta, H. pansarinii, and H. pansarinii var. minuscula. Habenaria campylogyna is proposed as a new name for the illegitimate H. humilis Cogniaux. The five species differ from other Neotropical taxa by being small, slender plants with linear leaves concentrated at the base of the stem. Molecular phylogenetic analyses based on nuclear and plastid DNA sequences revealed that they are not closely related, and do not belong to any of the previously identified Neotropical subclades. All of the new taxa were recovered in isolated positions, branching from basal nodes of larger subclades, suggesting that these morphological characters represent plesiomorphic traits in the Neotropical clade. Habenaria brachydactyla is genetically distinct and represents an early lineage of the Neotropical Habenaria clade. All taxa are considered threatened because of their small numbers of populations with few individuals and/or restricted distributions. Detailed descriptions, photographs, illustrations, notes, and a key to the species are presented.