A new species of Cirsium, Cirsiumtatakaense Y.H.Tseng & C.Y.Chang, from central-southern Taiwan is described and illustrated. This species is similar to C.kawakamii Hayata in leaf shape, achene and chromosome number (2n = 64), but can be readily distinguished from C.kawakamii by the narrower leaf lobes, usually higher number of florets and phyllaries, the purplish-red corolla (vs. white) and larger pollen grains. A key to the species of Cirsium in Taiwan is also presented.
Keywords: Cirsium kawakamii; Cirsium tatakaense; Compositae; Chromosome number; New species; Taiwan.