Systematics Section / ASPT
Morawetz, Jeffery J. , Randle, Christopher P. , Wolfe, Andrea D. .
Phylogeny and evolution of holoparasitism in the African clade of Orobanchaceae.
Parasitism in plants ranges from species that are still photosynthetic (hemiparasites), to those that have fully lost photosynthetic ability (holoparasites). Alectra is a primarily hemiparasitic genus that includes two holoparasitic species (A. alba; A. orobanchoides). Alectra alba is the least well known of these, occurring infrequently in forests in eastern-central Africa. Originally described as a species of Harveya, a primarily holoparasitic genus, this species was transferred to Alectra based on similarities in floral morphology (possessing the recurved style & stigma characteristic of Alectra). Vegetatively A. alba is quite distinct from other Alectra species in completely lacking pigmentation (the entire plant is white) and the scale-leaves typical of A. orobanchoides. Alectra alba is distinct from Harveya and other Alectra species in its host preference, growing on the roots of forest trees rather than parasitizing savanna grasses. Species of Harveya are generally thought to be holoparasites based on an achlorophyllous habit, with the exception of H. obtusifolia, which is by all appearances a hemiparasite, having chlorophyllous leaves that are not reduced to scales. This is the first phylogenetic analysis to include A. alba, and our combined three-gene dataset places it firmly within Harveya with high jackknife support. Further, the phylogenetic position of Harveya obtusifolia was examined.
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1 - Ohio State University, Department of Evolution, Ecology and Organismal Biology, 300 Aronoff Laboratory, 318 W. 12th Ave., Columbus, Ohio, 43210-1293, USA
2 - Sam Houston State University, Department of Biological Sciences, 1900 Avenue I., Huntsville, TX, 77340
Presentation Type: Oral Paper:Papers for Sections
Location: Stevens 2/Hilton
Date: Tuesday, July 10th, 2007
Time: 10:45 AM