Native to the United States, the adjacent Canadian provinces of Quebec and British Columbia, and Hawai`i.In the Hawaiian Islands,
indigenous to
Kaua`i, O`ahu, Moloka`i, Maui, Hawai`i.
Annuals; culms densely tufted, pale green, slender, 3-40 cm tall, 0.5-1.5 mm in diameter.
Leaves
Sheaths 1-6 cm long, the lower ones brownish purple, the orifice slightly oblique, margins tinged purplish.
Flowers
Spikelets densely many-flowered, ovoid to ovoid-ellipsoid, 5-13 mm long, 3-5 mm wide, obtuse; glumes brown, ovate to elliptic-ovate, 2-2.5 mm long, ca. 1.5 mm wide, obtuse, with a broad hyaline margin, the green midrib ending below the glume apex; bristles 6-7, brown, retrorsely spinulose, longer than the achene; style base deltoid, nearly as wide as the achene; stigmas 2-3.
Fruit
Achenes brown, glossy, smooth, obovoid, thickly biconvex with thickened angles, 1-1.5 mm long.
