Systematics/Phytogeography / Taxonomie/ Section
Burke, Janelle .
Systematics of Antigonon (Polygonaceae): towards a clear circumscription of A. leptopus.
Although Antigonon Endl. (Polygonaceae) is a small easily-recognized genus, the boundaries of species within it have never been resolved satisfactorily. Some investigators have recognized as many as eight species within the genus, while others have recognized just one polymorphic species. Specifically, the species circumscription of the polymorphic, invasive A. leptopus is still in flux. Although various segregate species have been proposed, suites of fixed morphological characters have not been identified. Here, a taxonomic treatment for the genus is proposed, based on floral morphology and molecular phylogenetic data from chloroplast markers. The molecular results corroborate a clear division in the genus based on morphology, and concordant with distribution, with one major evolutionary division in the genus strongly supported. The taxonomic difficulties in the genus are proposed to result from ongoing introgression between species, possibly linked to the widespread cultivation of A. leptopus within the native range of the genus. Nuclear markers are currently being used to investigate evidence of introgression of A. leptopus with other species. The proposed circumscription of A. leptopus is broad, and will impact the identity and management of invasive populations of Antigonon outside its native range.
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1 - Cornell University, L.H. Bailey Hortorium, 412 Mann Library Building, Ithaca, NY, 14853, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Room 1/Woodward
Date: Monday, July 28th, 2008
Time: 9:00 AM