Reid, Christopher .
Molecular Systematics of Cyperus L. (Cyperaceae): A Preliminary Analysis of Nuclear ITS Sequences.
Cyperus (flat sedges) has perhaps 700 species worldwide. Generic limits and infrageneric taxonomy of Cyperus are unclear. This study presents the results of an analysis of 50 ingroup OTUs, most of which were field collected during the growing season of 2010. In addition to Cyperus s.s., the ingroup included members of Kyllinga, Lipocarpha, Pycreus, and Queenslandiella. Previous molecular studies of Cyperus and tribe Cypereae have analyzed chloroplast markers using maximum parsimony. This study explores phylogenetic relationships within Cyperus s.l. using Bayesian analysis of nuclear ribosomal Internal Transcribed Spacer (ITS) sequences. The ITS tree, while not completely resolved, offers some interesting insights. Cyperus s.l. formed a well-supported clade, within which Kyllinga, Lipocarpha, Pycreus, and Queenslandiella were embedded. Within Cyperus s.l., two major clades corresponding to photosynthetic pathway (C3 and C4) were resolved. This C3/C4 split is consistent with previous cladistic analyses of chloroplast sequences. The C3 clade consisted of a polytomy involving three clades, one of which corresponding to the Luzulae group. Genus/subgenus Pycreus, diagnosed by lenticular achenes which are oriented edge-wise to the rachis of the spikelet, was polyphyletic in this analysis. The position of subgenus Diclidium within the tree suggests that the rank of section may be more appropriate. Future work will involve sequencing the ITS region for additional taxa. Other molecular markers such as matK will be sequenced and analyzed. Markers used by other workers will be sequenced in more New World taxa to enable a collaborative analysis of a larger taxon sample.
Log in to add this item to your schedule
1 - Louisiana State University, Biological Sciences, Life Science Annex Building, Rm. A257, Baton Rouge, LA, 70803, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell A/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 10:30 AM