Planetary Biodiversity Initiative (PBI): EuphORBia -a global inventory of the spurges Project Abstract This project provides a methodology to understand large and complex groups of organisms, using the spurge genus Euphorbia, with about 2000 species worldwide, as the model. Following field work in biodiversity hotspots and examination of museum collections and literature, the research team will produce updated lists and descriptions of all species, tools for amateurs and scientists to identify species, DNA sequencing analyses to determine evolutionary relationships, analyses of the distributions and rarity of endangered species, and evaluation of control methods for several noxious weedy species. There will be a core team of Euphorbia taxonomists worldwide, and the resulting information will be organized and conveyed by a separate team of bioinformatic specialists. This comprehensive study of a complex plant genus of over 2000 species in a 5-year time frame using mainly Internet-based tools will demonstrate the feasibility of obtaining and disseminating information quickly for other large and diverse groups of organisms. The project provides extensive training of students from K-12 to the postdoctoral levels, an educational outreach module using Euphorbia as an example, and a global approach to conducting scientific collaboration. It examines both the control of noxious weeds like the leafy spurge complex and the conservation of the 900-odd species of Euphorbia considered endangered by CITES.