Pupalia micrantha Hauman (Amaranthaceae), a Newly Naturalized Species in Taiwan

The specimens of Pupalia micrantha Hauman collected from southern Taiwan have been misidentified as Cyathula prostrata (L.) Blume for many years. This is because little attention was given to the diagnostic characteristics of pseudostaminodes and the hooked spines fascicled on a short stalk. The distinction between these two species is that Pupalia micrantha is without pseudostaminodes and the hooks are fascicled on a short stalk, and Cyathula prostrata has pseudostaminodes and the hooks are fascicled without peduncles. Therefore, Pupalia micrantha is a newly naturalized species of Amaranthaceae in Taiwan and represents the first generic record of Pupalia. This species was sparsely distributed for the past 20 years and is not recorded in the Flora of China. The taxonomic treatment, descriptions, photographs, line drawing, two keys about the subfamilies and genera of Amaranthaceae are provided here.