Scirpus cyperinus is perennial, C3 sedge (Bryson and Carter 1977) to 2 m tall; clumped, forming dense tussocks from short, tough rhizomes; stems upright, sparsely colonial from short rhizomes.
Leaves alternate, linear, 0.3-1 cm wide, bright green, rigid, basal leaves apparently resprouting in late fall, semi-evergreen (Gargiullo personal observation); base of leaf sheaths green to brown; inflorescence bracts leaf-like, unequal, tips drooping.
Flower spikelets 0.3-0.6 cm, egg-shaped, rusty-brown, numerous, clustered, bristles elongate, collectively making inflorescence appear wooly when mature; inflorescence stalks branched, open; blooming and fruiting Aug.-Oct. Seeds eaten by numerous water fowl and other birds, also small mammals
Wetland status: FACW+.
Frequency in NYC: Occasional.
Habitat: Open freshwater marshes, wet, low nutrient soil, pH 4.8-7.2 (USDA, NRDC 2010).
Notes: Stems and roots eaten by muskrats (Martin et al. 1951).