| Family | Sparganiaceae |
| Scientific name | Sparganium japonicum Rothert |
| Synonyms | none |
| Common name | (Japanese common name) nagae-mikuri (ナガエミクリ, 長柄実栗 [meaning: long stem maron fruits]) |
| (English common name) none | |
| Distribution | (Japan) Honshu, Shikoku, Kyushu |
| (Other nations) Korea | |
| Habitat | Swamp |
| Chromosomal number | 2n=30 |
| Description | Plants electing 35-100cm tall. Leaves 4.5-11mm wide. Flowers flowering in June to August. Perennial plants. |
| Reference | Sparganium japonicum Rothert |
| June 2009 at Ohsaka City University Botanical Garden |
June 2009 at Ohsaka City University Botanical Garden |
June 2009 at Ohsaka City University Botanical Garden |
| June 2009 at Ohsaka City University Botanical Garden |
June 2009 at Ohsaka City University Botanical Garden |