The species pictured here is the recently named hybrid between Japanese knotweed and giant knotweed, which has been named Bohemian knotweed. The hybrid strongly resembles Reynoutria japonica and most reports of the synonymous Polygonum cuspidatum in the literature for North America are actually the hybrid. The hybrid however has lobes at the leaf base rather than the truncate blade base of P. cuspidatum. Also known as `Japanese bamboo` because of the hollow, jointed stems. This species is often planted as an ornamental but persists and becomes invasive. It has moved into riparian communities in the west and often forms monocultural stands. This species has square leaf bases while the closely related R. sachalinense has larger leaves with lobed bases. The scientific name of Japanese knotweed in current use is Reynoutria japonica. Previous scientific names include Fallopia japonica, Polygonum cuspidatum, Polygonum sieboldii, Polygonum japonicum, Polygonum zuccharini, Pleuropterus zuccarinii, and Polygonum reynoutria (in USA horticulture trade). In Japan, the plant is commonly called itadori (meaning strong plant). In its introduced range, common names include Japanese knotweed, Sally rhubarb, donkey rhubarb, gypsy rhubarb, Hancock`s curse, Pysen saethwr, Gluineach bhiorach, Mexican bamboo, Japanese bamboo, Japanese fleece-flower, wild rhubarb, crimson beauty.
