Phylogeny in Chloranthus Swartz (Chloranthaceae) inferred from sequence analysis of nrDNA ITS region

The internal transcribed spacer (ITS) regions of nuclear ribosomal DNA from ten species of Chloranthus Swartz and two outgroup species of Sarcandra Gardn. were sequenced. The regions ranged in length from 654 to 663 bp, with ITS1 (285 - 290 bp) slightly longer than ITS:! (205 - 21.1 bp). Of the 669 aligned positions, 109 sites (56 in ITS1, 52 in ITS2, and one in 5.8S region) were phylogenetically informative. Only one most parsimonious tree of 252 steps was obtained in PAUP analysis when gaps were treated as the fifth state. The traditional division of Chloranthus on the basis of habit seems to be quite unnatural. Evidence from the sequence of ITS region, just as that from cytology and anatomy, strongly suggested the separation of the genus into two groups according to the characteristics of androecial organs: one contains C. angustifolius, C. nervosus, C. japonicus and C. fortunei, and the other comprises the remaining species.