MORTON, CYNTHIA M.*, NIGEL P. BARKER, AND H. PETER LINDER. Department of Botany, University of Reading, Whiteknights, Reading, RG6 2AS, UK, Department of Botany, Rhodes University, Grahamstown, 6140, South Africa, and Department of Botany, University of Cape Town, Rondebosch 7700, South, Africa. - Phylogenetic relationships of Cortaderia: cladistic analysis using the Nuclear Internal Transcribed Spacer region.
The grass genus Cortaderia (Pampas grass) as presently
circumscribed contains 24 species. The genus is distributed from
South America, New Zealand and New Guinea, although it occurs
predominantly South America. Cortaderia contains the greatest
concentration of gynodioecism in the Gramineae, however in some
species of Section Cortaderia only female plants are found. We
analyzed cladisitically ITS DNA (nuclear) sequences for 13 species
representing two of the four sections in the genus Cortaderia,
as well as related genera. The resulting tree showed
Cortaderia to be not monophyletic with members of the genera
Notochloe, Plinthanthesis, Danthonia and Lamprothyrsus
nested within this genus. Preliminary molecular systematic studies
based on chloroplast gene sequence data are in agreement with the
above results. Once these relationships were evaluated using
molecular data, we then concentrated on accumulating morphological
information for the above taxa. These results provide strong support
for a taxonomic realignment of Cortaderia and associated taxa.
Key words: cladisitic analysis, Cortedaria, Gramineae, ITS