CHANDLER, GREGORY T.* and GREGORY M. PLUNKETT. Department of Biology, Virginia Commonwealth University, Richmond, VA 23284. - Recent advances in the resolution of intra-ordinal affinities in the Apiales: evidence from 26S rDNA.
Relationships in the Apiales have been contentious throughout time,
and have only recently gained some stability through molecular
phylogenetic analysis. Past molecular work, utilizing the chloroplast
markers rbcL and matK, identifies five distinct groups
in the Apiales: the 'core' Apiaceae, the 'core' Araliaceae, the
Pittosporaceae, the Mackinlaya group, and the
Myodocarpus group. Recent work using the 26S rDNA region
complements these previous analyses, with the same five groups being
identified, strengthening support for this hypothesis. In particular,
our analysis shows that the apioid subfamily Hydrocotyloideae is
polyphyletic, which concurs with past analyses. The hydrocotyloid
genera occur in four lineages, including the 'core' Apiaceae, but also
in the 'core' Araliaceae, the Mackinlaya group, and the
subfamily Saniculoideae (Apiaceae). As a result, there are
evolutionary questions in the Apiales that need to be addressed, as
this subfamily was originally thought to be a 'bridging group' from
the 'primitive' Araliaceae to the 'advanced' Apiaceae. This will have
profound effects on our interpretation of morphological evolution in
the order.
Key words: 26S, Apiaceae, Apiales, Araliaceae, Hydrocotyloideae, Pittosporaceae