A New Species of Ladenbergia (Cinchoneae: Rubiaceae) from an Andean Tepui in Northeastern Peru

Abstract Ladenbergia shawistigma (Rubiaceae) is a new species from the Andean tepuis on the boundary of Loreto and San Martin departments in Peru. This new species is morphologically similar to L. moritziana and L. pauciflora, which are distributed in the Andean regions of Venezuela and Colombia, respectively. Ladenbergia shawistigma can be distinguished from these by the inflorescence resembling an umbelliform cyme with a short peduncle and three sessile flowers; hypanthium puberulous outside; small and deeply lobed calyx; and hirsute style. Ladenbergia shawistigma is only known from the Cordillera Escalera, Loreto, Peru.