Barkworth, Mary , Bushman, Shaun .
North American Meliceae (Poaceae): morphology, geography, and phylogeny.
The Meliceae, a basal pooid tribe, are represented in North America by four of its eight genera: Melica, Glyceria, Pleuropogon,and Schizachne. Melica grows in dry to moist sites but the other three genera grow in moist to wet habitats. Melica also differs from the other three genera in having a chromosome base number of 9 rather than 10. Six of the 36 North American species in the four genera extend across the northern part of the continent: G. borealis, G. grandis, G. striata, M.smithii, P. sabinei, and S. purpurascens. The remainder are either western or eastern in their distribution.There is also a marked morphological distinction between the western and eastern species of Melica but not Glyceria. Melica is also the only one of the four genera to be well represented in South America. Our preliminary work on the phylogeny of the tribe indicates that Glyceria is basal to the other three genera and that Pleuropogon is derived from it. Pleuropogon sabinei was sister to P. oregonus on both the ITS and cpDNA trees but relationships among other members of the genus differ between the two trees. Schizachne and Melica form a separate clade,with Schizachne basal to Melica. There is little molecular differentiation within North American members of Melica but the western and eastern species are in separate clades on the ITS tree and the eastern species appear to be more closely related to South American species than to the Asian or western North American species.Relationships on the chloroplast tree are unresolved. We plan to extend this work to other members of the tribe so that, in collaboration with others,relationships at the base of the Pooideae are clarified and a strong foundation developed for elucidating the genetic basis of the subfamily's success.
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Synopsis of information about the Meliceae derived from existing publications
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell A/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 10:00 AM