The United States hosts a remarkable floristic diversity of roughly 20,000 native species. According to the Center for Plant Conservation, nearly one-fifth of these species are of conservation concern, including 780 likely to be vulnerable to extinction in the next decade. For several of these species, rarity has resulted from natural processes, while others are threatened by exotic pests or pathogens, or by direct human impacts. This course will examine the factors that cause plants to be rare or imperiled, and the strategies employed to improve their long-term viability.
