Apiales

Abstract: Previous mapping studies have revealed that the frequency and large size of inverted repeat junction shifts in Apiaceae plastomes are unusual among angiosperms. To further examine plastome structural organization and inverted repeat evolution in the Apiales (Apiaceae + Araliaceae), we have determined the complete plastid genome sequences of five taxa, namely Anthriscus cerefolium (154,719 base pairs), Crithmum maritimum (158,355 base pairs), Hydrocotyle verticillata (153,207 base pairs), Petroselinum crispum (152,890 base pairs), and Tiedemannia filiformis subsp. greenmanii (154,737 base pairs), and compared the results obtained to previously published plastomes of Daucus carota subsp. sativus and Panax schin-seng. We also compared the five Apiaceae plastomes to identify highly variable noncoding loci for future molecular evolutionary and systematic studies at low taxonomic levels. With the exceptions of Crithmum and Petroselinum, which each demonstrate a ∼1.5 kilobase shift of its LSC-IRB juncti...

Abstract: Apiaceae and Araliaceae (Apiales) represent a particularly troublesome example of the difficulty in understanding evolutionary relationships between tropical-temperate family pairs. Previous studies based on rbcL sequence data provided insights at higher levels, but were unable to resolve fully the family-pair relationship. In this study, sequence data from a more rapidly evolving gene, matK, was employed to provide greater resolution. In Apiales, matK sequences evolve an average of about two times faster than rbcL sequences. Results of phylogenetic analysis of matK sequences were first compared to those obtained previously from rbcL data; the two data sets were then combined and analyzed together. Molecular analyses confirm the polyphyly of apiaceous subfamily Hydrocotyloideae and suggest that some members of this subfamily are more closely related to Araliaceae than to other Apiaceae. The remainder of Apiaceae forms a monophyletic group with well-defined subclades corresponding to subfamilies Apioideae and Saniculoideae. Both the matK and the combined rbcL-matK analyses suggest that most Araliaceae form a monophyletic group, including all araliads sampled except Delarbrea and Mackinlaya. The unusual combination of morphological characters found in these two genera and the distribution of matK and rbcL indels suggest that these taxa may be the remnants of an ancient group of pro-araliads that gave rise to both Apiaceae and Araliaceae. Molecular data indicate that the evolutionary history of the two families is more complex than simple derivation of Apiaceae from within Araliaceae. Rather, the present study suggests that there are two well-defined "families," both of which may have been derived from a lineage (or lineages) or pro-araliads that may still have extant taxa.

Abstract: Traditional classifications of Araliaceae have stressed a relatively small number of morphological characters in the circumscription of infrafamilial groups (usually recognized as tribes). These systems remain largely untested from a phylogenetic perspective, and only a single previous study has explicitly explored intergeneric relationships throughout this family. To test these infrafamilial classification systems, parsimony and Bayesian-inference analyses were conducted using a broad sampling of 107 taxa representing 37 (of the 41) genera currently recognized in core Araliaceae, plus five outgroup genera. Data were collected from two molecular markers, the internal transcribed spacers (ITS) of the nuclear rRNA genes and the intron and intergenic spacer found in the trnL-trnF region of the chloroplast genome. The results suggest that there are three major lineages of Araliaceae, and that these lineages generally correspond with the centers of diversity for the family. The Aralia and Asian Palmate groups are centered primarily in eastern and southeastern Asia, whereas the Polyscias-Pseudopanax group is found throughout the Pacific and Indian Ocean basins. Several poorly resolved lineages are placed at the base of core Araliaceae, and the geographic distributions of these clades are consistent with a hypothesized rapid radiation of Araliaceae, possibly correlated with the breakup of Gondwanaland. Comparison of molecular results with the traditional systems of classification shows almost no congruence, indicating that they inadequately reflect phylogenetic relationships. Moreover, the morphological characters employed in these classifications appear to be highly homoplastic, and are thus of little utility at the infrafamilial level.

Abstract: Previous attempts to resolve relationships among the primary lineages of Campanulidae (e.g. Apiales, Asterales, Dipsacales) have mostly been unconvincing, and the placement of a number of smaller groups (e.g. Bruniaceae, Columelliaceae, Escalloniaceae) remains uncertain. Here we build on a recent analysis of an incomplete data set that was assembled from the literature for a set of 50 campanulid taxa. To this data set we first added newly generated DNA sequence data for the same set of genes and taxa. Second, we sequenced three additional cpDNA coding regions (ca. 8,000 bp) for the same set of 50 campanulid taxa. Finally, we assembled the most comprehensive sample of campanulid diversity to date, including ca. 17,000 bp of cpDNA for 122 campanulid taxa and five outgroups. Simply filling in missing data in the 50-taxon data set (rendering it 94% complete) resulted in a topology that was similar to earlier studies, but with little additional resolution or confidence. In contrast, the addition of the ca. 8,000 bp of sequence data provided resolution and support for a number of relationships. With the addition of many more campanulid taxa we recovered a well-resolved phylogeny for Campanulidae where, with the exception of the placement of Escalloniaceae, support was high for all major clades. In addition, we were able to confidently place a number of enigmatic taxa, some whose relationships were previously unresolved and some never before included. In light of these results, we briefly expand the discussion of floral symmetry and provide a phylogenetic classification of Campanulidae with phylogenetic definitions for all well-supported major clades.