November 6th:
Jim Miller
 

"Resolving and applying a classification for the Borage family"

Boraginaceae are a family of about 135 genera and 2,500 species that remain poorly known. As methodology in systematics has evolved in the last 30 years, new evidence has helped resolve generic circumscription and produce a classification reflective of evolutionary relationships. Molecular data has confirmed that the traditionally recognized subfamilies are monophyletic, although the arrangement of genera within them has changed somewhat and the families Hydrophyllaceae and Lennoaceae nest within a broadly defined Boraginaceae. A robust subfamilial and generic classification has provided a framework for floristic studies and a recent review of the Boraginaceae from Madagascar allows the family to be used to identify conservation priorities.

October 16th:
Sang-Hun Oh
 

"Molecular phylogenetic systematics and biogeography of tribe Neillieae (Rosaceae)"

A phylogeny of the tribe Neillieae (Rosaceae), which comprises Neillia, Stephanandra, and Physocarpus, was reconstructed based on nucleotide sequences of several regions of cpDNA, the ITS and ETS regions of rDNA, and the second intron of LEAFY, to elucidate relationships among genera and species in Neillieae and to assess the historical biogeography of the tribe. Phylogenetic analyses indicated that Physocarpus and Neillia-Stephanandra were strongly supported as monophyletic and suggested that Stephanandra may have originated by hybridization between two lineages of Neillia. Dispersal-vicariance analyses suggested that the most recent common ancestor of Neillieae may have occupied eastern Asia and western North America and that Physocarpus and Neillia-Stephanandra may have been split by an intercontinental vicariance event. The biogeographic analyses also suggested that species of Neillia and Stephanandra diversified in eastern Asia, whereas in Physocarpus one dispersal event from western North America to eastern Asia occurred. The monotypic genus Guamatela placed in tribe Neillieae by Hutchinson in 1964 based on its follicular fruits and persistent stipules is anomalous in the tribe due to lack of endosperm. Phylogenetic analyses of chloroplast rbcL, atpB, and matK genes amplified from herbarium materials of Guamatela, along with sequences from representatives of most major eudicot groups, strongly supported Guamatela as a member of the rosid order Crossosomatales. None of the molecular data supported the inclusion of Guamatela in any described family in the order, and the unique combination of morphological characters did not fit the description of any of those families. Based on these results, the new family Guamatelaceae was proposed to accommodate this genus.

October 2nd:
Barbara A. Whitlock
University of Miami

"Systematics, biogeography, and the evolution of life histories in fringed gentians (Gentianopsis, Gentianaceae)"

The species of Gentianopsis (including the fringed gentians) are widely distributed in the northern hemisphere and vary in whole-plant morphology and life history. Previous studies, sampling few North American taxa, found the monotypic Asian genus Pterygocalyx nested within Gentianopsis and claimed an Asian origin for the clade containing both genera. Our phylogenetic analysis of plastid trnLF and nuclear ITS sequence data from 17 taxa of Gentianopsis, plus Pterygocalyx, with multiple individuals sampled for most taxa and increased representation of North American lineages, does not support Pterygocalyx nested within Gentianopsis. The geographical origin of the clade including both genera cannot be specified at present due to lack of resolution among potential outgroups. We find complex biogeographic patterns within the genus and within some species. There are at least two lineages of Gentianopsis in North America: the clonal perennial G. barbellata and G. simplex in western mountain ranges, and a large, widely distributed radiation of short-lived monocarpic taxa. The second lineage does appear to have originated in Asia and subsequently colonized North America, and its recognition as an evolutionary entity is a novel finding of our analysis. The hypothesis that effective generation time is negatively correlated with substitution rates has been applied to short-lived vs. perennial plants. We will discuss assumptions of this approach and other subtleties in testing this hypothesis. Multiple amplicons of ITS were recovered for nearly all specimens examined. In all but one case, ITS copies from each species form a monophyletic group, suggesting that concerted evolution is acting at a sufficient rate to resolve relationships among species. However, in well-sampled species, the multiple ITS sequences from a single individual rarely form a monophyletic group. The use of ITS sequences for phylogeographic or other population-level studies is thus problematical.