台灣新歸化水丁香屬（柳葉菜科）植物

Three Newly Naturalized Species of the Genus Ludwigia (Onagraceae) to Taiwan

水丁香屬植物爲柳葉菜科的一個大屬約共有80種。《台灣植物誌》第二版記載了6種及1天然雜交種。本研究報導3新歸化種，分別是歸化於台灣北部地區的沼生水丁香；歸化於台灣北部及中部地區的翼莖水丁香；以及歸化於台灣中部地區的美洲水丁香。本文提供台灣所產野生水丁香屬植物的檢索表，3種新歸化植物的描述、分布及彩色照片。

The genus Ludwigia comprises about 80 species. It is one of the largest genera of the family Onagraceae. Six species and one natural hybrid of Ludwigia have been recorded from Taiwan. In our recent plant inventory surveys, three species were found to be new records from Taiwan. They are Ludwigia palustris (L.) Elliott in the northern region, Ludwigia decurrens Walt. in the northern and central regions, and Ludwigia erecta (L.) Hara in the central region of the island. This paper describes these species of Ludwigia with photos and distribution, and provides a key to all ten naturally occurring species of Ludwigia in Taiwan for identification.