Distribution and genetic diversity of South Florida Tephrosia shed light on past cultural use

Societal impact statement A great many endangered plant taxa exhibit patterns of edaphic specialization, occurring on particular substrates such as karst or serpentine soils. Human activities, such as the construction of shell middens, can create edaphically unique substrates. In the Americas, post-Columbian land use changes coupled with extensive loss of indigenous cultural knowledge, has created areas where associations of cultivated plants with human-generated habitats may be lost. Here we use population genetic approaches to examine rare Tephrosia (hoary pea) taxa from South Florida, a group of plants that produce rotenone that has been used by many indigenous groups as a fish poison. We find evidence of multiple introductions from the broader Caribbean region and an association with anthropogenic habitats such as shell middens. In efforts to conserve rare hoary peas in Florida, an understanding of past use of the landscape by native Americans is essential. ### Competing Interest Statement The authors have declared no competing interest.