noun
Eleocharis kuroguwai; a species of spikerush
A specific aquatic plant native to Japan; the name is often used in botanical or agricultural contexts.
クログワイは水田で見られる多年草です。
Kuroguwai is a perennial plant found in paddy fields.
Refers to the edible corm of a related species; often distinguished from the native Japanese species by the cross-reference to 大黒慈姑.
See also: 大黒慈姑
クログワイの球茎は中華料理で使われる。
The corms of the Chinese water chestnut are used in Chinese cuisine.
Refers specifically to the Chinese water chestnut (Eleocharis dulcis), while クログワイ can refer to both the Japanese spikerush and the Chinese water chestnut.
The name クログワイ literally means 'black arrowhead' (黒慈姑), likely from the dark color of the plant's tubers. The exact origin is uncertain.