The genus Acalypha, commonly known as copperleaf, is the fourth largest genus in its family (Euphorbiaceae) with about 450 species. It is widespread geographically, with species native to the Americas (about two-thirds of the known species), Africa, Asia, Australia, and the Pacific Islands. It is most abundant and diverse in subtropical and tropical regions. Some species are problematic weeds in native and agricultural systems, whereas others are rare; two are common ornamentals, and there is growing evidence that some species contain potential pharmaceuticals. Unfortunately, the taxonomy of Acalypha has not been revised in more than 75 years and is suspected to reflect true relationships poorly. Ecological, conservation, pest management, and medical research on the genus are being hindered by the poor classification. Drs. Levin and Steinmann at the University of Illinois and the Institute of Ecology in Mexico intend to address this issue and provide better understanding of the evolution of the genus by using DNA sequence data and morphology to reconstruct the phylogeny, or evolutionary history, of a large sample of the genus. Combining field work and existing collections, they will examine about two-thirds of the species. Morphological data and sequence data from two genes (nuclear ITS and plastid ndhF) will be analyzed separately and in combination to reconstruct relationships within the genus. The results will then be used to revise the classification and assess various aspects of copperleaf evolution, particularly changes in growth form and reproductive organization. The investigators will develop a web site to distribute the results of this project and of future studies of Acalypha. This project is significant because it develops human resources, strengthens research on a poorly known group, stimulates further research, and facilitates conservation and pest management. Very few systematists work on Euphorbiaceae, especially given that the family is the seventh largest family of flowering plants with over 7,000 species. This project helps address this issue by providing training to a graduate student and a young researcher (Dr. Victor Steinmann). Further scientific work will be stimulated by providing the framework for other studies on a diverse group. Because of its simple flowers but varied ways of organizing them on the plant, Acalypha could become a model group for applying newly developed genomic techniques to understanding the evolution of floral development, but only if a well-supported phylogeny is available to provide the evolutionary context. In addition, Levin's and Steinmann's work will have broader societal benefits. A modern, well-supported classification will facilitate conservation of rare species, management of agricultural weeds and invasive species, and the search for pharmaceuticals.
