Schoenus nigricans is occasionally found growing in marshes, calcareous bogs, and wet flatwoods from the northern counties south to the central peninsula, and Escambia County (Wunderlin, 2003). It blooms from spring to summer. It occurs almost always (estimated probability 99%) under natural conditions in wetlands.
Black sedge might first be encountered as clumps of wiry stems and leaves, having blackish long-tipped clusters at the stem tips. Each cluster of blackish spikelets has one very long, stiff, pointed bract, jutting out from below.
Black sedge is a sedge. stems clump-forming, to 30 in. tall; squarish, smooth, wiry; leaf blades erect, wiry, thin, triangular, channeled; sheaths dark reddish brown to black; inflorescence at stem tip, dense cluster of very dark brown spikelets; bracts 1-2, one is to 3 in. long; spikelets narrow, pointed, scales in 2 rows, scales overlapping; nutlets glossy white, triangular, 3-6 short bristles