Japanese name: ウナギツカミ（鰻掴） Scientific name:Persicaria sagittata
[Overview]
An annual about 30–100 cm tall, found on riverbanks, in ditches and in wetlands.
The stem branches well; the lower part creeps along the ground, but the upper part rises and clambers over other plants.
The stem has 4 ridges, with downward-pointing prickles on the ridges.
Leaves are simple and alternate, arrowhead-shaped, 5–10 cm long and 2–3 cm wide, with downward-pointing prickles on the midrib of the underside.
The stipule sheath is tubular, with an obliquely cut tip.
A raceme shaped like a konpeito (a spiky sugar candy) arises at the stem tip.
There is no corolla; the calyx, white in the lower part and pale red in the upper part, is conspicuous.
The fruit is a triangular-pyramidal achene 2.5 mm long.
[Notes]
The Japanese name comes from the idea that one could grab an eel by using this prickly plant.
Some authorities treat Unagi-tsukami and Aki-no-unagi-tsukami as separate species.
