Taraxia is a small genus of flowering plants in the family Onagraceae (the evening-primrose family), comprising four accepted species. The genus is native to western North America, occurring across western Canada and the western and west-central United States.
Within the tribe Onagreae, molecular (nuclear DNA) evidence places Taraxia as the sister group to a clade that includes all other genera in the tribe except Oenothera, Eulobus, and Chylismia, reflecting its distinct but closely allied position within Onagraceae.
The four accepted species are Taraxia breviflora (Torr. & A.Gray) Nutt. ex Small, Taraxia ovata (Nutt.) Small, Taraxia subacaulis (Pursh) Rydb., and Taraxia tanacetifolia (Torr. & A.Gray) Piper. Species in this genus are low-growing herbaceous plants of open, often arid or semi-arid habitats across the intermountain and Pacific West regions.
Etymology
The genus name Taraxia is of botanical Latin origin. The name shares its root with Taraxacum (dandelion), derived from the Greek taraxos (disorder) or taraxis (disturbance), reflecting the turbid or disordered appearance applied historically to plants in this group; however, the precise motivating sense for Taraxia specifically is not explained in available sources.
Distribution
Taraxia is native to western Canada and the western and west-central United States. Its range spans the intermountain West and Pacific coast regions, where species occur in open, often arid habitats typical of the Onagraceae in that zone.
Taxonomy Notes
Nuclear DNA evidence places Taraxia as sister to a clade containing all genera of tribe Onagreae except Oenothera, Eulobus, and Chylismia. GBIF recognizes four accepted species under the genus in family Onagraceae. The genus was circumscribed following generic revisions that separated it from Camissonia and related segregate genera within Onagraceae; T. tanacetifolia was formerly placed in Camissonia before its transfer to Taraxia.
