Cirsiumtaiwanense (Compositae, Cirsiumsect.Onotrophe, subsect. Australicirsium), a new species from Taiwan

A new species of Cirsium, C.taiwanense Y.H.Tseng & Chih Y.Chang from central-northern Taiwan is reported in this article. This species is similar to C.hosokawae Kitam. in having a densely cobwebby abaxial leaf surface, but differs in its yellow (vs. vivid purplish red) corolla and the angle between the midrib and the lateral veins of the leaf, which is acute as opposed to nearly at a right angle in C.hosokawae. Cirsiumtaiwanense has 2n = 32 chromosomes, which is different from the other species in the Taiwanese subsect. Australicirsium Kitam. (2n = 34). An identification key to the Cirsium taxa of Taiwan is presented.