Publication: Sp. Pl. 1: 510.
Origin: Introduced from eastern North America
selected vouchers: WTU
Notes: FNA8: "Subspecies purpurea is introduced in California and Washington, in Europe in the British Isles and Switzerland, and in Japan. It is widespread and variable, and its adaptability is evidenced by the kinds of wetland habitats in which it grows. It is widely grown for ornament and teaching purposes and is the subject of much research on microorganisms and invertebrates, especially Wyeomyia Theobald mosquito larvae that live in the pitcher fluid."