A Review of Current Theories and Methods in Cladistics and a Cladistic Study of Twelve Lindera Species in Eastern China

Cladistics has become a widely used method for phylogenetic reconstruction．Because of rapid improvement Of cladistic theories and methodologies，and application of new data，especially，molecular data，it is becoming realistic to reconstruct phylogenies of organisms，and to establish natural classifications based on these phylogenies．This paper reviews some current cladistic theories and methods in a practical way，such as choosing characters，defining character states，polarizing characters，analyzing data matrices， calculating consensus cladograms，choosing among multiple equally most parsimonious cladograms，estimating reliability of cladograms，and applying cladograms to classification，character evolution，and biogeography． Based on 36 morphological characters．a parsimony analysis of 12 species representing six sections in subgenus Lindera and an outgroup species from subgenus lteodaphne of the genus Lindera(Lauraceae)was conducted．The results suggest a close relationship between section Lindera and section Sphaerocarpae，which is different from the previous phylogenetic hypothesis within the genus．In the strict consensus cladogram，two species，L．megaphylla and L.chienii，from section Cupuliformes are in the most primitive and the most advanced clades respectively，indicating that the section is polyphyletic．The cladogram also suggests that section Lindera be a polyphyletic group．