Abstract Detail

Systematics Section/ASPT

Doucette, Alfonso [1], McDaniel, James [2], Aprill, Laura [1], Chomitz, Isaac [1], Drees, Mark [1], Driscoll, Sarah [3], Griffay, Isabella [1], Lindop, Christina [1], Rashid, Julien [1], Cameron, Kenneth [4].

Preliminary Investigation into the Systematics and Biogeography of Masdevallia s.l.

The Student Chapter of the Botanical Society of America at the University of Wisconsin-Madison undertook a study combining phylogenetic and biogeographical analyses in order to investigate a large clade in one of the most species rich groups of orchids, the Pleurothallidinae, which accounts for 10-15% of all species diversity within the family. Despite their abundance, little research into their biogeography has been conducted, and our phylogenetic understanding of the relationships within the Pleurothallidinae is still in its infancy. This is partly due to the lack of robust phylogenies, and the contentious taxonomic circumscription of the genera. Here we focus on one of the most horticulturally important groups within the subtribe, which was traditionally circumscribed as the genus Masdevallia. Confusion regarding the genus’ circumscription has arisen due to homoplasious characters such as tailed sepals, which is the ancestral state for the clade, but have been independently evolved in other lineages within the subtribe, most notably Scaphosepalum and Dryadella. At present the Masdevallia clade is divided by Luer (2006), the current authority on the group, into 20 segregate genera based on “differences in morphology and DNA”. Most clades in the analysis by Abele et al. (2005; based on ITS) that Luer (2006) based his proposed circumscriptions on did not receive high support, and the utility of the characters in circumscribing the genera has not been analyzed. Here we sampled additional genes (XDH, matK) and more outgroups to test the monophyly of the proposed genera. In addition to molecular analyses, we analyze the morphological characters used to circumscribe the genera using parsimony in order to test their support for the groups. Proposed genera that were not recovered by the analyses were tested using constrained analyses in order to see whether monophyly could be rejected or not. The results of these phylogenetic analyses were also used in order to reconstruct the group’s ancestral area and determine how many times Central America was colonized by Masdevallia s.l. lineages and whether their distribution across the Andes shows phylogenetic signal.

1 - University of Wisconsin-Madison, Botany, 430 Lincoln Dr, Madison, Wisconsin, 53706, United States
2 - University Of Wisconsin - Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706, USA
3 - 699 W Mifflin St., Apt. 316, Madison, WI, 53703, USA
4 - University Of Wisconsin, Department Of Botany, 154 Birge Hall, 450 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Pleurothallidinae
Orchidaceae
systematics
Biogeography.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PSY006
Abstract ID:504
Candidate for Awards:None