List of Cirsium species

The following species in the flowering plant genus Cirsium, the plume thistles, are accepted by Plants of the World Online.[1] A 2022 molecular study reassigned many species to other genera, but Cirsium remains a speciose genus.[2] Already as a result of the genetic study Ackerfield et al. 2020, Cirsium and Carduus were determined to be polyphyletic in their current circumscriptions, suggesting to either "consolidate all taxa into one large genus (Carduus or Cirsium)," or "recognize each major clade as a genus (Carduus, Cirsium, Eriolepis, Notobasis, Picnomon, Silybum, and Tyrimnus)".[3] Bureš et al. 2023 examined ploidy, genome length, morphological similarity and other lines of evidence, reaching a similar conclusion; whereas the former study referred to a broader range of genera by the term "Carduus–Cirsium group", the latter was published on the heels of the separation of Lophiolepis and Epitrachys from Cirsium, so the focused shifted to their surprising result of Carduus and Tirymnus being nested within Cirsium.[4] Since further genetic evidence is needed to resolve the intergeneric relationships of the Carduinae, this list will be restricted to species in the current genus Cirsium.