Two Asteraceae plants naturalized in Taiwan, Erechtites hieraciifolius (L.) Raf. ex DC. (Asteraceae), and its variety, E. hieraciifolius (L.) Raf. ex DC. var. cacalioides (Fisch. Ex Spreng.) Griseb., are described in this research note. Erechtites hieraciifolius is naturalized in the lowlands of central and eastern Taiwan, while E. hieraciifolius var. cacalioides is naturalized in the lowlands and low elevations of southern Taiwan and Lanyu (Orchid Island). Color photos and a distribution map of E. hieraciifolius and E. hieraciifolius var. cacalioides are offered.