The Verbena family (Verbenasceae) is an important element in the New World flora, with approximately 1,000 species distributed primarily from the tip of South America to the SW US and with species extending as far north as Canada, Europe, and Africa. In Latin America it occurs from tropical wet forests to temperate deserts to high Andean ecosystems. One particularly interesting aspect of the distribution of these plants is the disjunct distribution of several genera between the arid regions of North America and South America, with a gap of several thousand miles between them. The classification of these plants is confusing and out of date with no recent systematic studies attempting to integrate across the entire family. This project will sample species throughout the family use the DNA sequences of several nuclear and chloroplast genes to reconstruct the phylogeny of this plant family and to use that tree of relationships to construct a more predictive classification and to test hypothesis of the origin and distribution of the species therein. The grant will support both field and laboratory research.
Biological classification is the language with which scientists communicate about the diversity of life on earth. The development of molecular approaches to understanding evolutionary relationships among species has permitted the establishment of consistent methods for the basis of classification. Thus, one significant result of this research will be a more useful classification of this group of plants for scientists worldwide to use. Patterns of plant distribution are tightly linked to environmental conditions where they occur. Plants in family Verbenaceae have diversified in arid in North and South America. One of the hypotheses that may explain this pattern postulates past climate change that has segregated what was once a continuous distribution into two widely separated regions. Understanding the historical patterns of plant distributions and the processes that may have given rise to them may help scientists to understand the potential changes in vegetation during the anticipated climate change period we are now entering. Since most of the diversity of this group of plants occurs in Latin America, Dr. Olmstead has established collaborations with scientists at several institutions in Central and South America. It is anticipated that this scientific exchange will benefit individual scientists both in the US and at those institutions through graduate student exchange (at least one University of Washington grad student will travel to Latin America and one Argentine grad student will travel to Seattle) and collaborative publication of the research results.
