Abstract
Eleocharis tsurumachii is a rare plant growing only at Kasumiga-ura Lake, and usually treated as infraspecific taxon of E. tetraquetra. Its morphology of hibernating buds on underground stolons was observed: buds ovate to longovate with acuminate top, 3-7mm long, 1.5-2.0mm wide, enclosed in scales as same long as buds. These characters are different from E. tetraquetra, therfore E. tsurumachii should be treated as a distinct species.
