Cyperus hypochlorus var. hypochlorus is a perennial herb, forming large, dense clumps with short, woody rhizomes clothed in dark reddish-brown or purplish-brown scales and their fibrous remnants. Its culms are stout, 50–130 cm tall, 5–16 mm in diameter at the base, trigonous, and smooth. The plant has several coriaceous leaves, linear and as long as or slightly longer than the culm, measuring 8–15 mm wide, with dark reddish-brown sheaths. It produces flowers in umbelliform, compound, or partially compound inflorescences that are moderately dense, 5–18 cm long, and 7–25 cm wide, with rays spreading 6–12, 3–16 cm long, once branched, each branch with 2–4 secondary rays, spikes cylindrical to oblong-elliptic, 2.5–4 cm long, 1.2–2 cm wide, densely bearing numerous spikelets. The spikelets are 3–8-flowered, widely spreading to slightly reflexed, linear-lanceoloid, subterete, slightly turgid, 6–16 mm long, 1.5–2.5 mm wide, rachilla broadly winged, glumes green and often tinged pale yellowish-brown, chartaceous with hyaline upper margins, oblong-lanceolate or oblong-elliptic, 3.5–5.5 mm long, 1.5–2.5 mm wide, laxly imbricate, suberect but those in the upper part of spikelet weakly spreading, 7–nerved or 9–nerved, midnerve prolonged into a minute recurved mucro. The achenes are oblong-ellipsoid, trigonous, 1.7–2 mm long, ca. 0.8 mm wide. The seeds are 1 per achene, with a thin seed coat, free from the pericarp, basal embryo, and abundant endosperm. It inhabits open sites in wet forests, especially waterways, and occasionally mesic forests between 850-1280 meters.