Flaveria linearis Lag. (Asteraceae), a shrub native to southern North America and Central America, has naturalized to the coast of Shenkang Hsiang, Changhua County, Taiwan. A taxonomic treatment, distribution and habitat, line drawings, color photographs and voucher specimens are provided to aid in identification of this alien plant. A detailed comparison between F. linearis and the closely related species, F. bidentis (L.) Kuntze, reported earlier as a naturalized species in Taiwan, is also provided.