Taxonomic notes on Plectocephalus ( Centaurea s.l., Centaureinae, Asteraceae) from Chile, including new combinations and synonyms

New taxonomic names and combinations are proposed for the genus Plectocephalus (Asteraceae) in Chile, which has traditionally been included within Centaurea s.l. Based on morphology and geographical distribution, new nomenclatural combinations for seven taxa and eleven new synonyms are given as well as complete descriptions of two species.