Tarennella, a new Pavetteae (Rubiaceae) genus from eastern Madagascar

Background – This contribution is part of an ongoing study on the taxonomy and phylogenetic relationships Malagasy representatives tribe Pavetteae (Rubiaceae).Material methods Taxonomic follow normal practice herbarium taxonomy. A molecular using plastid markers rps16, trnT-F, petD, accD-psa1, nuclear ribosomal marker ITS MADS-box gene PI was executed.Key results Five new species are described from littoral, lowland, or mid-elevation humid forests in eastern Madagascar. They characterized by compact inflorescences with small, sessile flowers, a densely pubescent style, large placentas 2–3 immersed ovules, seeds superficial hilum not surrounded thickened annulus, pollen grains supratectal elements. The tree, which included three five species, showed unresolved backbone but high support for distal nodes grouping species. form distinct monophyletic clade among other genera recognised at genus level under name Tarennella. Provisional IUCN Red List assessments show that Tarennella homolleana Vulnerable, T. cordatifolia sanguinea Endangered, puberula Critically coronata Endangered (Possibly Extinct).