Japanese name: アオガヤツリ（青蚊帳吊） Scientific name:Cyperus nipponicus var. nipponicus
[Overview]
An annual 5–25 cm tall, found in wetlands and on the banks between rice paddies.
It is rather soft; the stems grow in tufts and form a clump, and large clumps spread out radially.
The leaves are linear, 0.1–0.25 cm wide.
At the stem tip it produces an inflorescence of many densely crowded spikelets forming a sphere 1–2.5 cm in diameter, and the base has 3–4 long leaf-like bracts.
Sometimes it produces 1–5 inflorescence branches up to 5 cm long, each bearing a spherical inflorescence at its tip.
The spikelets are pale green, flat and lanceolate to narrowly ovate, about 0.3–0.7 cm long and 0.2 cm wide.
The scales are arranged densely in 2 rows; they are ovate to oval-ovate, about 2 mm long, and membranous, with a green midrib whose upper end tapers to an awn.
The fruit is elliptic to obovate, about 0.1 cm long, with slightly blunt edges; it is usually lens-shaped but may be 3-ridged.
[Notes]
The Japanese name comes from the green color of the inflorescence.
