The fern Pteris vittata, also known as brake fern, is a highly efficient hyperaccumulator of arsenic, capable of extracting and translocating large amounts of arsenic into its above-ground biomass. This plant is the first known fern to function as a hyperaccumulator and is highly effective in removing arsenic from contaminated soils. Brake fern was found growing on a site in Central Florida contaminated with chromated copper arsenate (CCA). Analysis of the plant's fronds revealed high levels of arsenic, with concentrations ranging from 3,280–4,980 p.p.m. in contaminated soils. Brake fern can accumulate arsenic efficiently from soils containing up to 1,500 p.p.m. arsenic, with arsenic concentrations in its fronds increasing dramatically within two weeks. The plant also shows high tolerance to various arsenic species, hyperaccumulating arsenic derived from compounds like FeAsO4 and AlAsO4. Brake fern is mesophytic, hardy, and grows in sunny, alkaline environments where arsenic is more available. It has a high biomass, grows quickly, and is easy to propagate. It is widely cultivated and naturalized in many areas with a mild climate, including the United States. Brake fern has great potential for remediating arsenic-contaminated soils and could also aid studies on arsenic uptake, translocation, speciation, and detoxification in plants. This is the first report of significant arsenic hyperaccumulation by an unmanipulated plant.The fern Pteris vittata, also known as brake fern, is a highly efficient hyperaccumulator of arsenic, capable of extracting and translocating large amounts of arsenic into its above-ground biomass. This plant is the first known fern to function as a hyperaccumulator and is highly effective in removing arsenic from contaminated soils. Brake fern was found growing on a site in Central Florida contaminated with chromated copper arsenate (CCA). Analysis of the plant's fronds revealed high levels of arsenic, with concentrations ranging from 3,280–4,980 p.p.m. in contaminated soils. Brake fern can accumulate arsenic efficiently from soils containing up to 1,500 p.p.m. arsenic, with arsenic concentrations in its fronds increasing dramatically within two weeks. The plant also shows high tolerance to various arsenic species, hyperaccumulating arsenic derived from compounds like FeAsO4 and AlAsO4. Brake fern is mesophytic, hardy, and grows in sunny, alkaline environments where arsenic is more available. It has a high biomass, grows quickly, and is easy to propagate. It is widely cultivated and naturalized in many areas with a mild climate, including the United States. Brake fern has great potential for remediating arsenic-contaminated soils and could also aid studies on arsenic uptake, translocation, speciation, and detoxification in plants. This is the first report of significant arsenic hyperaccumulation by an unmanipulated plant.