臺灣莧科新歸化種——小花鉤牛膝

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

採於臺灣南部的小花鉤牛膝（Pupalia micrantha Hauman）過去被鑑定為假川牛膝（Cyathula prostrata(L.) Blume），主要是沒注意到假雄蕊與鉤刺狀物叢生於短柄上等兩種特徵。兩種植物主要區別於鉤牛膝屬（Pupalia）不具有假雄蕊且鉤刺狀物叢生於短柄上，假川牛膝具有假雄蕊、鉤刺狀物叢生但不具有短柄。因此小花鉤牛膝為臺灣莧科新歸化種，鉤牛膝屬為臺灣莧科新記錄屬。小花鉤牛膝在過去20年間分佈數量不多，亦未見於中國植物誌。本文提供分類處理、形態描述、植物繪圖、照片及莧科植物亞科與屬的檢索表。

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.