Roraimaea (Gentianaceae: Helieae) is a new angiosperm genus from northern Brazil and southern Venezuela. This genus differs prominently from other taxa of the Gentianaceae tribe Helieae by its long-tubular, orange to red corollas, and deeply cleft styles with filiform lobes. Traditionally, pollen characters have been used as important traits to distinguish genera in the tribe Helieae. The pollen of Roraimaea is shed as tetrads and has an evenly thick, coarsely reticulate exine, which is similar to pollen occurring in Helia and Aripuana. Some similarities are also found with Aripuana cullmaniorum in the presence of dichasial inflorescences, erect flowers, and non-differentiated reticulate pollen tetrads. Phylogenetic studies have shown the distinctiveness of this taxon, as well as the need to move Rogersonanthus coccineus into this new genus. Roraimaea includes two species, Roraimaea coccinea comb. nov. from Serra de Neblina on the Brazil-Venezuelan border, and Roraimaea aurantiaca sp. nov. from lowland, white-sand campinas areas of Roraima State, Brazil.
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1 June 2008
Roraimaea (Gentianaceae: Helieae)—A New Gentian Genus from White Sand Campinas and Cerro de la Neblina of Brazil and Venezuela
Lena Struwe,
Siwert Nilsson,
Victor A. Albert
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biogeography
morphology
Neotropics
palynology
phylogeny
