Taxonomic Notes on Vanilleae (Orchidaceae - Vanilloideae) -- Vanilla dietschiana, a Rare South American Taxon Transferred from Dictyophyllaria

摘要

Tribe Vanilleae (Orchidaceae: Vanilloideae) consists of 10 genera including the monotypic Dictyophyllaria, which is endemic to Brazil. Dictyophyllaria dietschiana (Edwall) Garay has been segregated from Vanilla on the basis of its sympodial, non-climbing habit and reduced, reticulate-veined leaves. According to a recent phylogenetic analysis of Vanilleae based on two chloroplast regions (rbcL and psaB) and parsimony, Dictyophyllaria dietschiana is nested within Vanilla and closely related to V. edwallii Hoehne and V. parvifolia Barb. Rodr., two Brazilian species with membranaceous and reticulate-veined leaves. Based on such evidence, D. dietschiana is reinstated into Vanilla. A detailed morphological description of this endangered species, which hasrecently been considered possibly extinct, is also presented.