Abstract Detail

Systematics Section/ASPT

McCauley, Ross A. [1], Paces, Margo N. [1].

A preliminary analysis of phylogeography and species diversification of Ostrya (Betulaceae) in the southwestern US and Mexico.

In North America Ostrya has a wide rage extending from southeastern Canada to Honduras. In the northern part of this range it occurs as an understory tree in a variety of deciduous forest types and is represented by the relatively homogeneous taxon O. virginiana (Mill.) K. Koch. In the southwestern US and northern Mexico, Ostrya occurs in small populations which are highly disjunct in sheltered localities near moutaintops and deep canyonlands and include the two taxa O. knowltonii Coville and O. chisosensis Correll. Further south Ostrya is a cloud forest endemic across the major mountain ranges of Mexico extending into central Honduras. Taxonomically this region is typically considered as conspecific with O. virginiana representing one of a number of well-documented disjunctions between eastern North America and the mountains of Mexico. Using a combination of multivariate analysis of leaf variation and molecular phylogenetic data from three plastid regions (matK, psbA-trnH, and trnL-trnF) we show that the southwestern US and northwestern Mexico range consists of a single morphologicaly variable taxon. The Mesoamerican cloud forest accessions of Ostrya
show morphological variability intermediate to that seen in O. knowltonii and O. virginiana from Eastern North America. Haplotype diversity of these accessions shows a strong association to Eastern North America however a number of discrete instances of haplotype sharing with O. knowltonii suggest a complex pattern of historical gene flow with the southwestern US. This study identifies a number of regions which will be important for detailed analysis as we move forward on the taxonomic revision and detailed phylogeographic reconstruction of Ostrya across North America.

1 - Fort Lewis College, Department Of Biology, 1000 Rim Drive, Durango, CO, 81301, USA

Keywords:
Betulaceae
Ostrya
Phylogeography
Morphometrics
Mesoamerican Cloud Forest.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PSY016
Abstract ID:526
Candidate for Awards:None