title: The Taxonomic Significance of ducts in the corolla lobes of Vernonia (Vernonieae: Asteraceae).
abstract: The multiple longitudinal ducts in the corolla lobes found in the closely related genera Vernonia, Vernonanthura and Trepadonia are microscopically studied and illustrated. The lack of such ducts in the two South American species that have until now been retained in Vernonia indicates that they should probably be excluded from the genus.
authors.affiliation: Department of Botany, MRC 166, NMNH, P.O. Box 37012, Smithsonian Institution, Washington, DC. 20013-7012, USA.
authors.forename: Harold
authors.initials: H
authors.lastname: Robinson
authors.affiliation: Department of Botany, MRC 166, NMNH, P.O. Box 37012, Smithsonian Institution, Washington, DC. 20013-7012, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Yankowski
keywords: Ducts; Trepadonia; Vernonanthura; Vernonia; corolla lobes