おおくろぐわい (大黒慈姑)

Eleocharis dulcis

Eleocharis dulcis

Eleocharis dulcis

中国の揚子江沿岸が原産です。わが国に分布する「くろぐわい(黒慈姑)」の近縁で、中国南部から東南アジア、台湾などでは水田に栽培されています。高さは1メートルほどになり、茎は中空で丸く、内部には隔壁があり海綿質で満たされています。葉はふつう葉鞘だけで、茎の基部につきます。7月から10月ごろ、茎頂に円柱形の小穂をつけます。地下茎の先端につく直径3〜4センチの塊茎は食用になります。上海では地栗(di li)、広東では馬蹄(ma ti)と呼ばれ、中国料理の炒め物や餡かけなどに利用されます。台湾華語では「甜荸薺」。別名で「いぬくろぐわい(犬黒慈姑)」とも呼ばれます。
カヤツリグサ科ハリイ属の多年草で、学名は Eleocharis dulcis (syn. Eleocharis dulcis var. tuberosa)。英名は Chinese water chestnut。 
The Chinese water chestnut (Eleocharis dulcis) belongs to Cyperaceae (the Sedge family). It is a perennial herb that is native to the Yangtze River coast of China. It is a close relative of the "Kuro-guwai" (Eleocharis kuroguwai) distributed in Japan, and is cultivated in rice paddies from southern China to Southeast Asia, Taiwan, and other regions. The stems are hollow and round, with internal walls filled with spongy material. The leaves are usually only in leaf sheaths and are attached to the base of the stem, and from July to October, small cylindrical spikes are produced at the top of the stem. The 3- to 4-cm-diameter tubers attached to the tips of the underground stems are edible. It is called "地栗" (di li) in Shanghai and "馬蹄" (ma ti) in Cantonese, and is used in Chinese dishes such as stir-fried dishes and red bean paste. In Taiwanese Chinese, it is called "甜荸薺". It is also called "Inu-kuro-guwai" in Japan. 
大阪府交野市「大阪市大付属植物園」にて、2006年06月21日撮影。 

Shu Suehiro
shu@botanic.jp