もろこしそう (唐土草) [Index] [Back] わが国の固有種で、本州の関東地方南部以南から四国・九州、それに南西諸島や小笠原諸島に分布しています。海に近い暖地にある低地や山地の林内や林縁に生え、高さは２０〜８０センチになります。茎は直立または斜上して分枝します。葉は卵形で光沢があり、縁は波打ち、互生します。６月から９月ごろ、上部の葉腋に黄色い花を下垂して咲かせます。果実は球形の�刮ﾊで、灰白色に熟します。本種は、沖縄で古くから親しまれている伝統的な防虫・芳香植物です。和名は、むかし中国から渡来した植物と間違えて考えられていたことに由来します。また、別名で「やまくねんぼ（山九年母）」と呼ばれますが、これは山に生え、香りがミカン科の「くねんんぼ」に似ていることに由来します。 サクラソウ科オカトラノオ属の多年草で、学名は Lysimachia sikokiana。英名はありません。 The "Morokoshi-so" (Lysimachia sikokiana) belongs to Primulaceae (the Primrose family). It is a perennial herb that is endemic to Japan and is found from the southern part of the Kanto region on Honshu southward, as well as in Shikoku, Kyushu, the Nansei Islands, and the Ogasawara Islands. It grows in lowlands near the sea in warm regions, as well as within and along the edges of forests in mountainous areas, reaching a height of 20 to 80 cm. The stem is erect or ascending and branches. The leaves are ovate and glossy, with wavy margins, and are arranged alternately. From June to September, yellow flowers hang downward from the upper leaf axils. The fruit is a spherical capsule that ripens to a grayish-white color. This species is a traditional insect-repelling and aromatic plant that has long been cherished in Okinawa. Its Japanese name derives from the fact that it was once mistakenly believed to be a plant introduced from China in ancient times. It is also known by the alternative name "Yama-kunenbo", which stems from the fact that it grows in the mountains and its scent resembles that of "Kunenbo" (King tangor), a plant in the citrus family. 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