Tourn. ex L.
The genus Circaea contains 7–10 species of flowering plants, known as Enchanter's nightshade, in the willowherb family Onagraceae. They are woodland plants occurring throughout the temperate regions of the Northern Hemisphere. Two species are widespread, Broad-leaved Enchanter's Nightshade (Circaea lutetiana) and Alpine Enchanter's Nightshade (Circaea alpina). In addition, there is an intermediate hybrid between these two, and several local species or subspecies, with between eight and 14 forms recognised by different authorities. The hybrid is sterile, persisting only by vegetative reproduction and not producing seeds.
Circaea is in the family Onagraceae, which also includes willowherbs, evening primroses and fuchsias. The genus is named after the enchantress Circe from Greek mythology, who is supposed to have used enchanter's nightshade in her magic. Enchanter's nightshade is not related to the nightshade family that includes deadly nightshade and the Solanum genus (the Solanaceae). Molecular evidence indicates the closest relative to Circaea is the lineage that gave rise to the genus Fuchsia, which diverged from it around 41 million years ago.
- Circaea alpina (Alpine Enchanter's-nightshade)
- C. alpina subsp. alpina
- C. alpina subsp. angustifolia
- C. alpina subsp. caulescens
- C. alpina subsp. imaicola
- C. alpina subsp. micrantha
- C. alpina subsp. pacifica
- Circaea cordata
- Circaea erubescens
- Circaea glabrescens
- Circaea lutetiana (Enchanter's-nightshade)
- C. lutetiana subsp. canadensis
- C. lutetiana subsp. quadrisulcata
- Circaea mollis
- Circaea repens
- Circaea × intermedia (C. alpina × C. lutetiana) (Upland Enchanter's-nightshade)
- Berry, Paul E.; William J. Hahn; Kenneth J. Sytsma; Jocelyn C. Hall & Austin Mast (2004). "Phylogenetic relationships and biogeography of Fuchsia (Onagraceae) based on noncoding nuclear and chloroplast DNA data". American Journal of Botany 91 (4): 601–14.