Systematics Section / ASPT
Dragon, Julie A. , Barrington, David S. .
The systematics and biogeography of the Carex aquatilis group, section Phacocystis (Cyperaceae).
PHYLOGENETIC analyses of nuclear and chloroplast DNA sequences support the monophyly of the highly diverse Carex aquatilis group, including Carex aquatilis and C. lenticularis, and their allies, of section Phacocystis. Neither C. aquatilis nor C. lenticularis, however, are monophyletic as circumscribed. The sequence data could not resolve the relationships among the four varieties of C. aquatilis and their maritime allies from the C. subspathacea group. The western varieties of C. lenticularis are not sister to the eastern type variety. Three of these varieties represent a morphologically diverse species, C. kelloggii, and exhibit little genetic variation from the most recent common ancestor of their clade. The other variety is polyphyletic and comprises two species, C. enanderi (Alberta to Alaska) and C. plectocarpa (Montana). Carex decidua is also polyphyletic. A population from Colombia is molecularly and morphologically distinct from typical C. decidua from southern South America. It is most similar to C. hermannii, however, an exhaustive study of other Northern Andean populations is necessary before we can determine its specific status. The C. aquatilis group now comprises 14 species (C. aquatilis, C. subspathacea, C. ramenskii, C. paleacea, C. lyngbyei, C. kelloggii, C. enanderi, C. hermannii, C. cuchumatanensis, C. lenticularis, C. decidua, C. rufina, C. eleusinoides, and C. plectocarpa) and is supported by molecular, morphological, and ecological data. Biogeographic analyses indicate a mid-Pleistocene origin for the group around 0.88 mya from a North American ancestor.
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1 - University of Vermont, Department of Botany, 109 Carrigan Drive, Burlington, Vermont, 05405-0086, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 11:15 AM