Carex grayi Carey. is a perennial sedge (family Cyperaceae) that grows in tufts of solitary or multiple stems up 1.1 m (~3.6 ft) high and is wind-pollinated. It can be found in rich, mesic soils of forests, calcareous seepage swamps, marshes, banks, and wet meadows, within riparian systems. Its distinctive inflorescence can be observed from mid-summer into fall. The large, air-filled perigynia are likely to float for extended periods, taking their achenes away from the parent plant.
Gray’s sedge is a clump-forming plant with short rhizomes and triangular culms (reproductive stems). The pale or gray-green leaves are 4-11 mm (0.16-0.43 in) wide with persistent basal reddish-purple sheaths. The subtle narrow peduncled staminate spike is located above one or two large spherical pistillate spikes on the same stem. The densely flowered female spikes are subtended by long, leaf-like bracts that do not have sheaths.
 
Here is the reference for this species:
Massachusetts Executive Office of Energy and Environmental Affairs. “Gray’s Sedge (Carex grayi).” Mass.gov, 26 Mar. 2025, https://www.mass.gov/info-details/grays-sedge.