"Bontoku-tade" (Persicaria pubescens) belongs to Polygonaceae (the Knotweed family). It is an annual herb that is distributed in various parts of Japan, as well as in China, Malaysia, and India. It grows near water or in wetlands near human settlements and grows 70 to 100 cm tall. The leaves are broadly lanceolate and alternate, with an eight-characters black spot in the center. Around September to October, it produces long, narrow, racemes that hang down, producing small white to light red flowers. The Japanese name "bontoku-tade" comes from the fact that the leaves are not pungent and useless, although they resemble the "yanagi-tade" (smartweed) used as a spice. "Bontoku" means "fool" in Japanese.