Assessment of Matourea pratensis (Plantaginaceae: Gratioleae) reveals an older name for Achetaria

Abstract

Matourea pratensis is a name published by Aublet in 1775 that has never been typified and whose identity has long been obscure. It was historically associated with Stemodia foliosa, as S. pratensis, a species with reported medical importance and wide distribution in the Neotropics. However, its morphology has also been interpreted as more similar to Achetaria, a genus widely distributed throughout the Neotropics and also with medicinal, ecological and economic value. After an extensive bibliographical survey, along with morphological study of type specimens of M. pratensis, S. foliosa, and Achetaria spp., we conclude that (1) S. foliosa and M. pratensis represent distinct taxa; and (2) M. pratensis is congeneric with Achetaria. As a result, we transfer the currently accepted species of Achetaria to Matourea, proposing eight new combinations (M. azurea, M. caparaoensis, M. crenata, M. erecta, M. latifolia, M. ocymoides, M. platychila, M. scutellarioides). Additionally, we designate lectotypes for M. pratensis, Tetraplacus platychilus f. longifolius, Otacanthus caparaoensis, O. fluminensis, and O. villosus, and a second-step lectotype for Beyrichia scutellarioides.