selected vouchers: WTU
Notes: FNA19: "In most American floristic literature Acroptilon has been included within Centaurea, from which it differs by the subbasal rather than lateral attachment scars on the cypselae and the absence of sterile outer florets. The chromosome base number. = 13 is higher than that in most species of Centaurea in the strict sense. Molecular phylogenetic studies of the relationships of Cynareae genera (A. Susanna et al. 1995) support the segregation of Acroptilon from Centaurea."