China contains some of the world's greatest diversity of Apiaceae (Umbelliferae),
with ten endemic genera. Our previous investigation into the phylogenetic relationships
of Chinese Apiaceae subfamily Apioideae, based exclusively on nrDNA ITS sequences,
revealed several major clades heretofore unrecognized in the subfamily and confirmed
the phylogenetic placements of five endemic genera. To further elucidate relationships
among Chinese Apioideae, ascertain the phylogenetic placements of the remaining endemic
genera, and test hypotheses of relationships proposed in our earlier study, additional
taxa were examined for ITS and, for smaller sets of accessions, cpDNA rpl16 and rps16
intron sequence variation. These ITS and cpDNA data matrices comprised 158 and 131
accessions, respectively, with 110 accessions included in the analysis of combined
ITS and cpDNA data. Maximum parsimony and Bayesian analyses of partitioned ITS and
chloroplast data sets resulted in highly consistent phylogenies, whereas analyses
of combined molecular data resulted in trees of greatest resolution and overall branch
support. Two major clades identified in our previous study are recognized at the tribal
level: Komarovieae J. Zhou & S. R. Downie trib. nov. and Chamaesieae J. Zhou & F.
D. Pu trib. nov. The monotypic tribe Chamaesieae represents one of the earliest diverging
lineages of subfamily Apioideae in Asia. The Acronema and East Asia clades of previous
circumscription are each expanded. Of the five Chinese endemic genera not examined
previously, Chaerophyllopsis finds affinity within tribe Scandiceae subtribe Scandicinae,
Chuanminshen allies with Changium and Cyclorhiza in tribe Komarovieae, Harrysmithia
falls within the Acronema Clade, Melanosciadium embeds in Angelica in tribe Selineae,
and Dickinsia is confirmed as a member of Apiaceae subfamily Azorelloideae. The cpDNA-based
phylogenies are not sufficiently resolved in their distal portions to elucidate the
tribal placement of the endemic genus Nothosmyrnium, whereas the ITS trees strongly
indicate an affinity with tribe Pimpinelleae. The affinities of several Chinese endemic
species are also addressed. Peucedanum delavayi, for example, is phylogenetically
distant from Sinodielsia and Meeboldia, genera with which it has been allied previously,
and shows close affinity to three Chinese species of Ligusticum in tribe Selineae.
Aside from providing a framework for taxonomic revisions, the phylogenetic structure
recovered in this study for subfamily Apioideae will lay the foundation for future
investigations of evolutionary patterns of morphological characters and biogeography.