SPEER, WILLIAM D.* and PAUL G. WOLF. Department of Biology, Utah State University, Logan, UT 84322 USA. - A phylogenetic study of the genus Equisetum using chloroplast and nuclear DNA.
The findings of a phylogenetic study of the genus Equisetum
using both chloroplast and nuclear DNA sequences are presented and
discussed. Analyses of chloroplast rps4 sequences indicate three
distinct clades within the genus: (1) "traditional" subgenus
Equisetum minus E. bogotense, (2) subgenus
Hippochaete, and (3) E. bogotense. These rps4-based
findings are consistent with inferences of a previous study (by Des
Marais et al.) that used (chloroplast) rbcL and trnL-F sequences. We
also amplified an (nuclear) ITS (ribosomal RNA internal transcribed
spacer) region. We found a consistent PCR product size different
between the two subgenera; E. bogotense shared the subgenus
Equisetum haplotype. However, because of alignment difficulties and
lower resolution, the ITS data are not incongruent with the
"three clade" hypothesis based on chloroplast DNA data.
Key words: Equisetum, ITS, phylogeny., rps4