Flora of the Hawaiian Islands
Monocotyledon Literature for Cyperus difformis
Wagner et al., 1990, 1999.
   Cyperaceae -- The Sedge Family Bibliography
      Cyperus difformis
General Information
DistributionNative to warm temperate and tropical regions worldwide in wet places, presumably originally distributed only in the Old World.In the Hawaiian Islands, naturalized on Kaua`i, O`ahu, Maui, Hawai`i.

Annuals with purple fibrous roots; culms tufted in small or relatively large clumps, pale green, erect to slightly spreading, soft, trigonous, the angles acute, (10-)25-60 cm tall, 2-5 mm in diameter.
Leaves numerous, slightly shorter than the culm, blades pale green, soft, linear, 2-6 mm wide, folded, gradually tapering to an acute apex; sheaths pale brown or yellowish brown.
Corymbs simple or compound, 2-6 cm long and as wide, primary rays 3-9, unequal in length, 1-4 cm long, secondary ones, when present, up to 1 cm long, each ray tipped with a dark green or brownish green globose cluster of numerous spikelets, 5-15 mm in diameter; involucral bracts 2-3, up to twice as long as the corymb; spikelets 8-28-flowered, lanceolate to linear-lanceolate, compressed, 2-8 mm long, ca. 1 mm wide, rachilla not winged; glumes dark green, tinged purplish brown, membranous, laxly spaced, suborbicular, 0.5-0.8 mm long and as wide, faintly 3-nerved, the keel yellow, apex rounded; style ca. 1/2 as long as the achene; stigmas 3.
Achenes yellow at maturity, ovoid-ellipsoid, trigonous, nearly equalling the glume.
2n = 26, 34, 36