Abstract Detail

Systematics Section/ASPT

McDaniel, James [1], Cameron, Kenneth [2].

Preliminary molecular data partially supports previous taxonomic treatments of the Neotropical orchid genus Porroglossum.

Within Orchidaceae, the largest, most diverse family of plants, lies subtribe Pleurothallidinae, which contains >4,000 species in 35 genera accounting for 17% of orchid diversity. Many of these genera are native to Neotropical biodiversity “hotspots”, such as the cloud forests of the Andes, which means they may be at a high risk of extinction due to habitat loss, global climate disruption, and low rates of pollination and fruit set. The genus Porroglossum is composed of 49 described species that are distributed throughout South America from Venezuela south to Colombia, Ecuador, Peru, and Bolivia. If Charles Darwin, the author of The Power of Movement in Plants, had known about Porroglossum surely he would have been intrigued by the lip that, when stimulated, actively snaps inward thrusting pollinators against the column to ensure pollination. In the past, molecular data was not used to infer evolutionary relationships among species of the genus; however, the genus was treated taxonomically using morphological characters. Luer (1987) divided the genus into two subgenera: Eduardia and Porroglossum, with the latter split into three sections: Echidnae, Porroglossum, and Tortae. Nearly two decades later, Aubron (2005) divided the genus into three subgenera: Eduardia, Echidnae, and Porroglossum. Subgenus Porroglossum was further split into two sections, Tortae and Porroglossum, with the latter divided into three subsections: Porroglossum, Brevisepala, and Mordax. Recently, we reconstructed the phylogeny of Porroglossum and appropriate outgroups using a combination of nuclear (nrITS and XDH) and plastid (matK, ycf1, accD-psaI, and rpl32-trnL) sequences for half of the species within the genus, which provides an adequate representation of the groups taxonomically treated by Luer (1987) and Aubron (2005). Three clades were recovered with strong support for the following taxa: Echidnae (99% bs), Brevisepala (95% bs), and Porroglossum (95% bs). Furthermore, species of the group Tortae (99% bs) form a clade within the taxon Porroglossum. Preliminary results regarding implications for classification will be discussed in conjunction with future avenues of research that will potentially shed light on the mechanism(s) responsible for active movement in the lip, plant-pollinator relationships, and floral fragrance patterns. 

1 - University Of Wisconsin - Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706, USA
2 - University Of Wisconsin, Department Of Botany, 154 Birge Hall, 450 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Orchidaceae
Pleurothallidinae
Andes
phylogenetics
taxonomy.

Presentation Type: Oral Paper:Papers for Sections
Session: 31
Location: Pines South/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 4:30 PM
Number: 31011
Abstract ID:490
Candidate for Awards:None