Eleocharis engelmannii is an annual spike rush, 5-50 cm tall, clumped, roots short, fibrous (easily pulled up), stems 0.1-0.2 cm thick.
Leaves bladeless, sheaths only.
Flowers in cone-shaped inflorescence (spikelet) 0.5-1.3 cm long, scales dark, red-brown with green center stripe (becoming pale with age), margins pale, membranous.
Fruit a dry achene, lens-shaped, narrow at base, with broad-based, hat-like short beak; blooms and fruits Aug.-Oct. Seeds eaten by waterfowl and shorebirds (Martin et al. 1951).
Wetland status: OBL.
Frequency in NYC: Occasional but listed as Endangered in New York State.
Habitat: Shallow water or saturated soil in open areas or partial shade, wet fill, soil pH 4.6-6.8; tolerant of fire, intolerant of shade and salt (USDA, NRCS 2010).
Notes: Plants eaten by muskrats and rabbits (Martin et al. 1951). Synonyms: E. ovata var. engelmannii; E. ovata var. obtusa; E. engelmannii; E. obtusa; E. obtusa var. detonsa; E. obtusa var. engelmannii; E. obtusa var. jejuna; E. obtusa var. ovata. (see Flora of North America Editorial Committee, eds. 1993+.)