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Japanese knotweed, Water pepper, Lamb's Quarters, Common Chickenweed, Cleavers
Useful plant polygonum
Polygonum is a genus of about 220 species of flowering plant in the buckwheat and knotweed family Polygonaceae. Common names include knotweed, knotgrass, bistort, tearthumb, mile-a-minute, smartweed and several others. In the Middle Englishglossary of herbs Alphita (c. 1400-1425), it was known as ars-smerte. There have been various opinions about how broadly the genus should be defined. For example, Buckwheat (Fagopyrum esculentum) has sometimes been included in the genus as Polygonum fagopyrum.
The genus primarily grows in northern temperate regions. The species are very diverse, ranging from prostrate herbaceous annual plants under 5 cm (2 in) high to erect herbaceous perennial plants growing up to 3–4 m (10–13 ft) tall to perennial woody vines growing up to 20–30 m (66–98 ft) high in trees. Several are aquatic, growing as floating plants in ponds. The smooth-edged leaves range from 1–30 cm (0.39–11.81 in) long, and vary in shape between species from narrow lanceolate to oval, broad triangular, heart-shaped, or arrowhead forms. The stems are often reddish or red-speckled. The small flowers are, pink, white, or greenish, forming in summer in dense clusters from the leaf joints or stem apices.
The genus name is from the Greekpoly = "many" and gonu = "knee" or "joint", in reference to the swollen jointed stem.
Polygonum species are occasionally eaten by humans, and are used as food plants by the larvae of some Lepidoptera species - see list. Most species are considered weedy, especially in moist soils in the USA.
Lady s thumb polygonum persicaria luminearth s how to identify wild edible medicinal plants
Distribution and uses
Several species can be eaten cooked, for example during famines. The species Polygonum cognatum, known locally as "madimak", is regularly consumed in central parts of Turkey.
In Chinese medicine, a Polygonum extract called Rèlínqīng Kēlì (热林清颗粒) is used to treat urinary tract infections. Chinese medicine also uses a Polygonum multiflorum extract called Fo-Ti.
Care should be taken not to confuse Polygonum with Polygonatum - an entirely different genus of plants.
Species
Between 65 and 300 species have been recognised at various times, depending on the circumscription of the genus. About 200 species are currently accepted. A number of species that had been included in Polygonum have been moved into several other genera, including Fagopyrum, Fallopia, Persicaria and Reynoutria.
Accepted species include:
Polygonum achoreum S.F. Blake
Polygonum affine D.Don (Persicaria affinis is a synonym)
Polygonum species that have been reclassified as Reynoutria
Polygonum multiflorum Thunb. is a synonym of Reynoutria multiflora (Thunb.) Moldenke
Polygonum cuspidatum Siebold & Zucc. is a synonym of Reynoutria japonica Houtt. - Japanese knotweed
Polygonum sachalinense F.Schmidt is a synonym of Reynoutria sachalinensis (F.Schmidt) Nakai – giant knotweed
Unresolved species
Polygonum bistortoides Pursh - American bistort, western bistort, smokeweed or mountain meadow knotweed - may be synonymous with the unresolved species Bistorta bistortoides (Pursh) Small
Polygonum odoratum Lour. – Vietnamese coriander is an unresolved species name. Persicaria odorata may be a synonym.
Polygonum tenuicaule Bisset & S.Moore is an unresolved species name. Persicaria tenuicaulis may be a synonym.
Polygonum vaccinifolium Wall. is an unresolved species name. Persicaria vaccinifolia may be a synonym.
Polygonum davisiae W.H. Brewer ex A. Gray and Polygonum newberryi Small are synonyms of Aconogonon davisiae (Brewer) Soják, an unresolved species name - Newberry knotweed
Polygonum filiforme Thunb. is a synonym of Antenoron filiforme (Thunb.) Roberty & Vautier which is an unresolved species name
