Japanese name: ママコノシリヌグイ（継子尻拭） Scientific name:Persicaria senticosa
[Overview]
A climbing annual found on riverbanks and by roadsides.
The stem branches well and, clambering over other plants, grows to 1 m long, with sharp downward-pointing prickles.
Leaves are simple and alternate, triangular, 3–8 cm long and 3–7 cm wide.
Bristly hairs grow on the veins of the underside of the leaf.
The petiole is almost as long as the leaf.
The stipule sheath is leaf-like, large and kidney-shaped to rounded.
A short, spherical raceme arises at the stem tip.
There is no corolla; the calyx, white in the lower part and red in the upper part, is conspicuous.
The fruit is a spherical black achene 2–3 mm in diameter.
