Evolution of morphological traits in Verbenaceae

O'LEARY NATALY; CALVIÑO CAROLINA; MARTÍNEZ SUSANA; OLMSTEAD, RICHARD; MÚLGURA MARÍA EMA

AMERICAN JOURNAL OF BOTANY

BOTANICAL SOC AMER INC

Lugar: St. Louis; Año: 2012 vol. 99 p. 1778 - 1792

0002-9122

Premise of the study: A new infrafamilial circumscription of the Verbenaceae with eight tribes: Casselieae, Citharexyleae,Duranteae, Lantaneae, Neospartoneae, Petreeae, Priveae, and Verbeneae, has been recently proposed, on the basis of molecularphylogenetic studies. Two genera, Dipyrena and Rhaphithamnus , remain unplaced. The aim of this work is to reconstruct theevolutionary history of morphological characters traditionally employed in the classifi cation of the Verbenaceae, with specialattention to tribes Verbeneae and Lantaneae.Methods: Twenty-one characters, related to habit and vegetative morphology, inflorescence and floral morphology, ovary andfruit morphology, as well as chromosome number, were optimized over a molecular phylogeny of Verbenaceae.Key Results: All tribes are supported by at least one morphological trait except tribes Duranteae and Citharexyleae. Suffrutescenthabit, sessile flowers, and four cluses are synapomorphies for tribe Verbeneae. Gynoecium with short style and entire stigmaare synapomorphic traits for tribe Lantaneae. Sessile flowers and unicarpellate ovaries are morphological synapomorphies forthe new tribe Neospartoneae. Suffrutescent habit is a synapomorphic trait for tribe Priveae. Homothetic pleiobotrya andabsence of the adaxial staminode are synapomorphic traits for tribe Casselieae. Undivided fleshy fruits are probably a synapomorphictrait for tribe Petreeae. Putative plesiomorphies for the ancestor of the Verbenaceae are discussed as well as synapomorphictraits within other Verbenaceae clades.Conclusions: Many of the characters traditionally employed in classification have proven to be very homoplastic, or have beenshown not to support relationships within the family. Moreover, traditional assumptions concerning character polarity have insome cases been shown to be incorrect.