PANERO, JOSE L.1*, BRUCE G. BALDWIN2, EDWARD E. SCHILLING3, and JENNIFER A. CLEVINGER4. 1Section of Integrative Biology, University of Texas, Austin, TX 78712; 2Jepson Herbarium & Dept. of Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, University of California, Berkeley, CA 94720-2465; 3Department of Botany, University of Tennessee, Knoxville, TN 37996-1100; 4Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807. - Molecular phylogenetic studies of members of tribes Helenieae, Heliantheae, and Eupatorieae (Asteraceae). 2. Tribal/generic relationships.
Molecular phylogenetic studies of 123 genera belonging to tribes
Helenieae, Heliantheae and Eupatorieae of the HHE clade reveal novel
relationships for several members of these tribes. The genera
Phaneroglossa (Senecioneae) and Inula (Inuleae) were chosen as
outgroups. Parsimony analysis of the data matrix produced 8640 trees
of 11090 steps (CI 0.5654 excluding uninformative characters, RI
0.6605). After analysis of the data matrix and the resulting
phylogenetic hypothesis we conclude that the genera Athroisma and
Blepharispermum are not members of the HHE clade and should either be
recognized as a separate tribe or reincorporated into the Inuleae, as
they share numerous synapomorphies with the outgroup. The basalmost
lineage of the HHE clade contains the genera Psathyrotes, Marshallia,
Helenium, Hymenoxys, and Psilostrophe. These genera, along with a few
others classified by previous authors in either subtribes
Marshalliinae or Gaillardiinae, are here included in a narrowed
interpretation of tribe Helenieae. Dahlia and Coreopsis are sister and
constitute the next sublineage to diverge. Their basally divergent
position is somewhat surprising although morphologically they are a
very distinct group that we recognize as tribe Coreopsideae. In some
of the most parsimonious trees we observed that a majority of the
epaleate genera centered about Bahia, Chaenactis, and Hymenopappus and
previously classified in tribe Helenieae s. l., the traditional
helianthoid taxa Polymnia, Enydra, and subtribe Neurolaeninae are
grouped in a clade sister to a large clade containing most members of
tribe Heliantheae, Eupatorieae and the tarweeds and relatives. In the
strict consensus tree this intriguing clade collapses leaving a
polychotomy with the genera Varilla and Jaumea as single lineages,
Enydra sister to Neurolaeninae, the epaleate helenioid genera grouped
in a clade with moderate support, and Polymnia sister to Oxypappus.
Key words: Asteraceae, chloroplast DNA, Eupatorieae, Helenieae, Heliantheae, phylogenetics