  persicaria perfoliata (syn. polygonum perfoliatum) is a species of flowering plant in the buckwheat family, polygonaceae. common names include mile-a-minute weed, devil's tail, and giant climbing tearthumb. it is a trailing herbaceous annual vine with barbed stems and triangular leaves. it is native to most of temperate and tropical eastern asia.persicaria perfoliata. grin taxonomy for plants. == appearance == it has a reddish stem that is armed with downward pointing hooks or barbs which are also present on the underside of the leaf blades. the light green colored leaves are shaped like an equilateral (equal-sided) triangle and alternate along the narrow, delicate stems. distinctive circular, cup-shaped leafy structures, called ocreas, surround the stem at intervals. flower buds, and later flowers and fruits, emerge from within the ocreas. flowers are small, white and generally inconspicuous. the fruits are attractive, metallic blue and segmented, each segment containing a single glossy, black or reddish-black seed. == habitat == persicaria perfoliata weed generally colonizes open and warm areas, along the edges of woods, wetlands, stream banks, and roadsides, and uncultivated open fields, resulting from both natural and human causes, dense wooded areas where the overstory has opened up increasing the sunlight to the forest floor. natural areas such as stream banks, parks, open space, road shoulders, forest edges and fence lines are all typical areas to find p.&nbsp;perfoliata. it also occurs in environments that are extremely wet with poor soil structure. available light and soil moisture are both integral to the successful colonization of this species. it will tolerate shade for a part of the day, but needs a good percentage, 63-100% of the available light. the ability of p.&nbsp;perfoliata to attach to other plants with its recurved barbs and climb over the plants to reach an area of high light intensity is a key to its survival. it can survive in areas with relatively low soil moisture, but demonstrates a preference for high soil moisture. == introduction in the united states ==  the first records of persicaria perfoliata in north america are from portland, oregon (1890) and beltsville, maryland (1937). both of these sites were eliminated or did not establish permanent populations of the species
Invasive_plant_species_in_the_United_States Leaf_vegetables Persicaria Plants_described_in_1759