Phylogeny of the tribes Juanulloeae and Solandreae (Solanaceae)

Abstract

The tribe Juanulloeae is composed of seven to nine Neotropical genera of lianas and epiphytic or terrestrial shrubs that exhibit a wide variety of floral morphologies and pollination syndromes. Their commonly epiphytic habit in the forest canopy and relatively infrequent flowering has resulted in few and fragmentary specimens and has complicated taxonomic study of the tribe so that many of its genera remain poorly understood. Solandra, currently included in the monotypic tribe Solandreae, is morphologically very similar to the Juanulloeae but its phylogenetic affinities are unclear. In this study, a phylogeny of the Juanulloeae and Solandra was inferred from maximum parsimony and Bayesian analyses of nuclear and plastid DNA sequences (ITS, waxy, trnT-trnF, rps16-trnK). Solandra was strongly supported as sister to the Juanulloeae and the two tribes are combined here under the older name Solandreae. Many genera within the group, notably Juanulloa, Markea, and<br />Trianaea, are not monophyletic as currently circumscribed. We review the morphological characteristics of the genera and clades in light of the phylogenetic evidence presented here and highlight the need to re-evaluate the morphological characters used to delimit genera of the tribe. On the basis of our results, we propose to (1) broaden the circumscription of tribe Solandreae to include tribe Juanulloeae, (2) recognize nine genera in the Solandreae, including the reinstatement of Poortmannia and Hawkesiophyton, and (3) make two new species-level combinations, propose one new species-level synonym, and designate<br />a lectotype for Trianaea neovisae.