<i>YANOMAMUA ARACA</i> (GENTIANACEAE), A NEW GENUS AND SPECIES FROM SERRA DO ARAÇÁ, AN OUTLIER OF THE GUAYANA REGION IN AMAZONAS STATE, BRAZIL

<i>Yanomamua araca</i> is described as a new genus and species from Serra do Araçá, an outlier of the Guayana Region in the state of Amazonas, Brazil. <i>Yanomamua</i> is unique in the Gentianaceae as an herb with sessile subcordate pandurate (fiddle-shaped) leaves, and inflorescences composed of oppositely paired solitary flowers situated in the axils of the upper three leaf pairs. Only limited material is available, and flower morphology is unknown. A phylogenetic approach was used to investigate possible relationships to other genera in Helieae, which yielded a likely relationship to several genera in the <i>Symbolanthus-Chelonanthus</i> clade but not a strong relationship to any particular genus. Instead it appears that this genus might represent a more internal, older branch within the tribe.