a perennial herb, 0.4-1m in height, occurs in flatland wetlands,
its thick rhizomes extending suckers long to build colonies. Stems,
3-ridged, are extensive, with rugged leaves, in a linear shape.
Spikelets are 4-7 in number; the terminals are male, the other
lateral ones, tingeing dark brown, linear, 4-7cm in length, and the
lateral spikelets, 3-10cm in length,5mm in with, cylindrical, are
females. Bloom time: April-July.