たいわんとりあし (台湾鳥足) [Index] [Back] わが国の南西諸島、屋久島および種子島から奄美群島の奄美大島と徳之島、沖縄群島の沖縄島、八重山群島の石垣島、それに台湾や中国南東部に分布しています。低地の林下に生え、高さは５０〜１００センチになります。葉は卵形から披針形で葉紙質、縁には鋸歯があり、対生します。７月から１０月ごろ、葉腋に穂状花序をだし、小さな淡黄白色の花を多数咲かせます。雌雄同株で、茎の上部に雌花序、下部に雄花序がつきます。果実は倒卵形の痩果です。基本種の「ながばやぶまお」（３倍体で無融合生殖）とは異なり、２倍体で有性生殖を行います。環境省のレッドリストでは絶滅危惧II類（ＶＵ）に指定されています。台湾華語では「台灣苧麻」、中国語では「海島苧麻（hai dao zhu ma）」と呼ばれます。 イラクサ科カラムシ属の多年草で、学名は Boehmeria formosana。英名は Formosan false-nettle。 The Formosan false-nettle (Boehmeria formosana) belongs to Urticaceae (the Nettle family). It is a perennial herb that is distributed throughout Japan's Nansei Islands -including Yakushima and Tanegashima- as well as Amami Oshima and Tokunoshima in the Amami Islands, Okinawa Island in the Okinawa Islands, Ishigaki Island in the Yaeyama Islands, and in Taiwan and southeastern China. It grows in lowland forests and reaches a height of 50 to 100 cm. The leaves are ovate to lanceolate, papery in texture, serrated along the margins, and arranged in opposite pairs. From July to around October, it produces panicles in the leaf axils, bearing numerous small, pale yellowish-white flowers. It is monoecious, with female inflorescences on the upper part of the stem and male inflorescences on the lower part. The fruit is an obovate achene. Unlike the basic species, "Nagaba-yabumao" (a triploid that reproduces asexually through agametophyte), this species is diploid and reproduces sexually. It is classified as Vulnerable (VU) in the Ministry of the Environment's Red List. It is called "台灣苧麻" in Taiwanese Chinese and "海島苧麻" (hai dao zhu ma) in Chinese. 茨城県つくば市「つくば実験植物園」にて、2026年03月28日撮影。 Shu Suehiro shu@botanic.jp