Japanese name: イシミカワ Scientific name:Persicaria perfoliata
[Overview]
A climbing annual found on riverbanks and roadsides.
The stem twines around other plants, growing 1–2 m long, and has sharp, downward-pointing prickles.
The leaves are simple and alternate, triangular, 2–4 cm long and 3–5 cm wide, with the petiole attached peltately near the base.
The petiole also has downward-pointing prickles.
The ocrea (sheath formed by the stipules) is leaf-like, large and round, and clasps the stem.
Short racemes emerge at the stem tips or leaf axils.
The flowers are pale green and have no corolla.
The inflorescence bears round, shield-shaped bracts.
The fruit is a spherical achene 2–3 mm across, glossy and black.
The calyx, which persists until the fruiting stage, turns a vivid blue and wraps around the fruit.
[Uses]
The whole plant is called kobanki (杜板帰) and is used medicinally.
