Native to subtropical and tropical regions worldwide.In the Hawaiian Islands,
naturalized on
Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Hawai`i.
Habitat
Wet, disturbed sites, especially in bogs, wet forest, and open, muddy areas
Elevation
3-1700 m
Habit
Perennials with reddish purple fibrous roots, rhizomes slender, horizontal; culms tufted with a short rhizome, or solitary and arranged in a row along an elongate rhizome, erect, slender, rather soft, trigonous, usually 10-50 cm tall.
Leaves
Leaf blades linear, up to 2/3 as long as the culm, 2-5 mm wide, apex long acuminate, or leaves reduced to bladeless sheaths at base of culms; sheaths pale green and usually tinged with brown, purplish brown, or reddish purple, 2-10 cm long.
Flowers
Corymbs compound or simple, rather lax, 8-15 cm long and as wide, primary rays several, unequal, the longer ones 5-10 cm long, slender, the secondary rays, when present, few, up to 2 cm long; involucral bracts 1-2, the longest one equalling to slightly shorter than the corymb; spikelets 4-8 per cluster, densely 10-28 flowered, digitately disposed at apices of primary or secondary ray, linear oblong, flattened, 5-15 mm long, 1-1.5 mm wide, apex obtuse, rachilla not winged; glumes pale brown and often tinged or variegated with rusty brown or purplish brown, membranous, elliptic to lanceolate elliptic or narrowly ovate, ca. 1.5 mm
long, slenderly 3 nerved, the keel green, midnerve prolonged into a short straight mucro; stamens 1-3; style 1.5 times as long as the achene; stigmas 3.
Fruit
Achenes pale yellow, obovate, trigonous, ca. 0.5 mm long, tuberculate.
