MOLECULAR SYSTEMATICS OF APIACEAE SUBFAMILY APIOIDEAE - PHYLOGENETIC ANALYSES OF NUCLEAR RIBOSOMAL DNA INTERNAL TRANSCRIBED SPACER AND PLASTID RPOC1 INTRON SEQUENCES

Evolutionary relationships among representatives of Apiaceae (Umbellif erae) subfamily Apioideae have been inferred from phylogenetic analyse s of nuclear ribosomal DNA internal transcribed spacer (ITS 1 and ITS 2) and plastid rpoC1 intron sequences. High levels of nucleotide seque nce variation preclude the use of the ITS region for examining relatio nships across subfamilial boundaries in Apiaceae, whereas the rpoC1 in tron is more suitably conserved for family-wide phylogenetic study but is too conserved for examining relationships among closely related ta xa. In total, 126 ITS sequences from subfamily Apioideae and 100 rpoC1 intron sequences from Apiaceae (all three subfamilies) and outgroups Araliaceae and Pittosporaceae were examined. Phylogenies estimated usi ng parsimony, neighbor-joining, and maximum likelihood methods reveal that: (1) Apiaceae subfamily Apioideae is monophyletic and is sister g roup to Apiaceae subfamily Saniculoideae; (2) Apiaceae subfamily Hydro cotyloideae is not monophyletic, with some members strongly allied to Araliaceae and others to Apioideae + Saniculoideae; and (3) Apiaceae s ubfamily Apioideae comprises several well-supported subclades, but non e of these coincide with previously recognized tribal divisions based largely on morphological and anatomical characters of the fruit. Four major clades in Apioideae are provisionally recognized and provide the framework for future lower level phylogenetic analyses. A putative se condary structure model of the Daucus carota (carrot) rpoC1 group II i ntron is presented. Of its six major structural domains, domains II an d III are the most, and domains V and VI the least, variable.