Persicaria longiseta

Persicaria longiseta is a species of flowering plant in the knotweed family known by the common names Oriental lady's thumb, bristly lady's thumb, Asiatic smartweed, long-bristled smartweed, low smartweed, Asiatic waterpepper, bristled knotweed, bunchy knotweed, and tufted knotweed. It is native to Asia (China, India, Russia, Japan, Malaysia, etc.), and it is present in North America and Europe as an introduced species and often a weed. Persicaria longiseta is an annual herb with stems 30 to 80 centimeters (12–32 inches) long, sometimes reaching one meter (40 inches). The hairless, branching stems may root at lower nodes that come in contact with the substrate. The leaves are lance-shaped and up to 8 centimeters (3.2 inches) long by 3 cm (1.2 inches) wide. They have bristly ochrea. The inflorescence is an elongate cluster up to 8 centimeters (3.2 inches) long and contains many pink flowers. The fruit is a small, smooth achene. In its native region this plant is a common weed of rice pa......read more on Wikipedia.