<i>Lapaea</i> (Plantaginaceae, Gratioleae), a new genus endemic to the Espinhaço Range (Brazil) with a remarkable red-flowered new species

<i>Stemodia</i> sensu lato is one of the largest genera of the Gratioleae (Plantaginaceae). Recent phylogenetic studies corroborated the paraphyly of <i>Stemodia</i> in its traditional circumscription and suggested the segregation of <i>S. stellata</i> from this genus. This species belongs to a morphologically cohesive group along with <i>S. cipoensis</i>, <i>S. harleyi</i> and <i>S. lobata</i>, all endemic to the Espinhaço Range, eastern Brazil. In this study, we tested the monophyly and interspecific relationships of this group by reconstructing its phylogeny, based on sequences of three cpDNA regions (<i>rps16</i> and <i>trnL</i> introns and the <i>trnL</i>–<i>trnF</i> intergenic spacer), and one nrDNA region (ITS1 spacer), using Maximum parsimony and Bayesian inference. The monophyly of the '<i>S. stellata</i> group' was confirmed, and its segregation from <i>Stemodia</i> corroborated. We propose <i>Lapaea</i> as a new genus to accommodate its species, with subsequent four new combinations: <i>L. cipoensis</i>, <i>L. harleyi</i>, <i>L. lobata</i>, and <i>L. stellata</i>. Additionally, we describe and illustrate <i>L. rubriflora</i>, a remarkable red-flowered new species, based on morphological and micromorphological evidence. Lastly, a taxonomic revision of the species recognized in <i>Lapaea</i> is presented, providing an identification key, photos, descriptions, distribution map and notes on their morphology, geographic distribution, habitat, ecology, and conservation status. <i>Lapaea</i> is restricted to the Espinhaço Range comprising five threatened species, each of them with a narrow distribution and phylogenetic relationships consistent with biogeographic provinces.