Publication: In I. Dörfler, Herb. Norm. 44: 108. (as Heleocharis).
selected vouchers: Not at WTU; WS?
Notes: FNA23: "Eleocharis mamillata has been confused in North America with E. macrostachya and E. palustris. In addition to the perianth bristle and achene differences as given in the key, E. mamillata differs from E. palustris in culm stomate shape and distance between epidermal collenchyma strands (S. M. Walters 1953b; S.-O. Strandhede and R. Dahlgren 1968). Eleocharis mamillata subsp. mamillata, with the tubercle mamillate, usually shorter than wide, and subsp. austriaca (Hayek) Strandhede, with the tubercle conic, longer than wide, are recognized in Europe; in North America only E. mamillata subsp. mamillata is thus far known. The stamen filaments usually remain attached to the shed achenes, and together with the bristles they keep the achenes in ball-like aggregates that drift with winds and water currents (S.-O. Strandhede 1966)."