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Abstract Detail



Systematics Section/ASPT

Oldham, Karoline [1], Weeks, Andrea [2].

The taxonomic revision and historical biogeography of the hemiparasitic annual wildflower, Melampyrum lineare (Orobanchaceae).

American cow-wheat (Melampyrum lineare Desr.) is a hemiparasitic angiosperm distributed in North American temperate mid- to high-latitude or high-elevation forests that contain its preferred host tree species. It is the sole North American species of its genus, which comprises another 34 species in Eurasia. Four varieties of Melampyrum lineare are recognized: M. lineare var. latifolium Barton, M. lineare var. pectinatum (Pennell) Fernald, M. lineare var. americanum (Michaux), and M. lineare var. lineare. However, their morphology and geographic distributions have not been revised since the 1930’s, nor is it clear whether they warrant recognition as separate taxonomic entities. Moreover, we do not know how M. lineare established its current distribution in North America, as all other Melampyrum species are distributed in Eurasia. For my masters’ thesis research, I am testing two hypotheses proposed by Francis Pennell in his 1935 work, The Scrophulariaceae of Eastern Temperate North America.. The first, regarding M. lineare’s relation to other members of its genus, proposed that M. pratense was the likely progenitor of M. lineare. I have collected sequence-based genetic data in order to infer relationships between M. lineare and other members of its genus. Pennell’s second hypothesis addresses M. lineare’s historical distribution, and proposes that the species survived Pleistocene glaciations in southern Appalachia and subsequently recolonized the formerly glaciated territory to the north. To test this hypothesis, I will assess the population genetic diversity of this species across its range using microsatellite markers, under the assumption that populations distributed in former refugial areas in southern Appalachia will harbor greater genetic diversity than those in northern or western North America. The population genetic data will also be used to assess the conservation genetic status of the rare, threatened or endangered populations in Indiana, Kentucky and Ohio. Phylogeographic analysis of M. lineare will elucidate how a hemiparasite migrated throughout eastern North America following Pleistocene glaciations, and will assess the conservation genetics of this species in light of threats from global climate change.

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1 - George Mason University, School of Systems Biology, 4400 University Drive, David King Hall MS 3E1, Fairfax, VA, 22030
2 - George Mason University, 4400 University Drive MSN 5F2, Fairfax, VA, 22030

Keywords:
Phylogeography
Melampyrum lineare
North America.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PSY049
Abstract ID:747
Candidate for Awards:None


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