This is one of the largest Eleocharis species and may first be noticed as a patch of dark green stems growing in the water on the edge of a canal, having conspicuous light brown cylindrical spikes at the tips. Eleocharis interstincta is occasionally found growing in the wet ditches and pond margins of the central and southern peninsula of Florida, and Franklin and Holmes counties. It blooms from spring to summer. This Eleocharis is one of 30 species that exist in Florida (Wunderlin, 2003). Jointed spikerush occurs in AL, FL, TX; and in PR and the Virgin Islands (Kartesz, 1999).
Jointed spikerush is a sedge. Stems erect, firm, round, 16-48 in. tall, to 1/2 in. across; conspicuous cross hatching (light green lines) at stem walls, closer nearer the top; leaf blades none, just sheaths; sheath thin, soft, red; inflorescence a single spikelet, about as wide as stem, at stem tip, cylindrical, long, to 2 in. long, scale tops very rounded; flowers many, whitish; nutlets rounded, surrounded by barbed bristles.