Schoenoplectus hotarui

Japanese name: ホタルイ （蛍藺）
Scientific name: Schoenoplectus hotarui

[Overview]
An annual 20–60 cm tall, found in paddy fields, fallow paddies, wetlands and the edges of ponds and marshes from lowlands to mountains.
The rhizome is not developed.
Many stems emerge, cylindrical, 19–73 cm long and 0.5–2 mm wide, with no nodes above the base.
The leaves are basal, usually reduced to projections, and the leaf sheaths form tubes 3–11 cm long.
1–4 spikelets gather at the stem tip to form the inflorescence, but because the involucral bract stands upright, the inflorescence appears to be lateral.
There is usually one involucral bract, which is culm-like, upright and 4–15 cm long.
The spikelets are ovate, 6–15 mm long, and stalkless.
The scales of the spikelet are ovate, 4–5 mm long, with blunt to slightly pointed tips and membranous margins.
The anthers are 1.2–1.8 mm long, and the style usually divides into 3 branches.
There are 5–6 bristle-like perianth segments, slightly shorter or slightly longer than the fruit, rough in a downward direction.
The fruit is slightly glossy blackish brown, broadly obovate with 3 angles, 1.8–3 mm long and 1.5–2.2 mm wide, with transverse wrinkles.

[Notes]
The name is said to derive from its growing at the waterside where fireflies live.

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