Polygonum

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Polygonum

Polygonum maritimum, sea knotgrass

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Caryophyllales
Family:	Polygonaceae
Genus:	Polygonum L.

Species

Between 150-300 species; see text

Polygonum is a genus in the buckwheat family Polygonaceae. The name may be derived from the Greek poly, "many" and gonu, "knee" in reference to the swollen jointed stem nodes.^[1] There is another theory which states that the second part of the name is derived from Greek gonos, "children"^{[citation needed]} or gone, "seed"^[1]. Common names include knotweed, knotgrass, bistort, tear-thumb, and several others. In the Middle English glossary of herbs "Alphita" (ca. 1400-1425), it was known as ars-smerte^[2]. There have been various opinions about how broadly the genus should be defined. Buckwheat for example has sometimes been included in the genus.

The genus primarily grows in northern temperate regions. They vary widely from prostrate herbaceous annual plants under 5 cm high, others erect herbaceous perennial plants growing to 3–4 m tall, and yet others perennial woody vines growing to 20–30 m high in trees; several are also aquatic, growing as floating plants in ponds. The smooth-edged leaves vary greatly in shape between species, and can be narrow lanceolate, oval, broad triangular, heart shaped or arrowhead shaped; they range from 1–30 cm long. The stems are often reddish or red-speckled. The flowers are small, pink, white, or greenish, forming in summer in dense clusters from the leaf joints or stem apices.

Polygonum species are used as food plants by the larvae of some Lepidoptera species - see list of Lepidoptera that feed on Polygonum, a number are considered weedy, especially in moisture retentive soils in the USA.

1 Distribution and Uses
2 Species
3 References/External links
4 References

[edit] Distribution and Uses

At least one species has been eaten during times of famine.^[3]

[edit] Species

Between 65^[1]–300 species are recognised depending on the circumscription of the genus; some botanists divide the genus up into several smaller genera, including Fagopyrum, Fallopia and Persicaria.

The genus Polygonella has a number of morphological similarities with Polygonum and some authors have included Polygonella in Polygonum.^[1]

Selected species include:

Polygonum achoreum
Polygonum acuminata
Polygonum acuminatum - tapertip smartweed
Polygonum arenarium
Polygonum arenastrum – small-leaved knotgrass
Polygonum argyrocoleon
Polygonum arifolium
Polygonum aviculare – common knotgrass
Polygonum bellardii
Polygonum bidwelliae
Polygonum bistortoides
Polygonum bolanderi
Polygonum boreale
Polygonum brasiliensis
Polygonum bungeanum - Bunge's smartweed
Polygonum buxiforme
Polygonum caespitosum
Polygonum californicum – California knotweed
Polygonum careyi - Carey's smartweed
Polygonum cascadense
Polygonum caurianum
Polygonum chinense
Polygonum coccineum
Polygonum cognatum – Indian knotgrass
Polygonum davisiae
Polygonum densiflorum
Polygonum dibotrys
Polygonum douglasii – Douglas' knotweed
Polygonum erectum
Polygonum flaccidum – (Meissn.)
Polygonum foliosum
Polygonum forrestii
Polygonum fowleri
Polygonum franktonii
Polygonum glaucum
Polygonum griffithii
Polygonum herniarioides
Polygonum heterosepalum – dwarf desert knotweed
Polygonum hickmanii
Polygonum hirsutum
Polygonum hongkongensis
Polygonum hudsonianum
Polygonum hydropiperoides - swamp smartweed
Polygonum lacerum
Polygonum lanigerum
Polygonum marinense
Polygonum maritimum – sea knotgrass
Polygonum meisneranum
Polygonum meisnerianum
Polygonum minimum – broadleaf knotweed
Polygonum multiflorum
Polygonum newberryi - Newberry knotweed
Polygonum oxyspermum – Ray's knotgrass
Polygonum paronychia
Polygonum paronychioides
Polygonum parryi
Polygonum patulum - Bellard's smartweed
Polygonum perfoliatum – mile-a-minute weed
Polygonum phytolaccifolium
Polygonum plebeium
Polygonum polycnemoides
Polygonum polycnenoides
Polygonum polygaloides
Polygonum punctatum - dotted smartweed
Polygonum raii = Polygonum oxyspermum
Polygonum ramosissimum
Polygonum robustius - stout smartweed
Polygonum rurivagum
Polygonum salicifolium
Polygonum scoparium
Polygonum segetum - field smartweed
Polygonum setaceum - bog smartweed
Polygonum shastense
Polygonum striatulum
Polygonum tenue

[edit] Reclassified as Fagopyrum

Polygonum fagopyrum (Fagopyrum esculentum) – buckwheat

[edit] Reclassified as Fallopia

Polygonum aubertii = Polygonum baldschuanicum
Polygonum baldschuanicum (Fallopia baldschuanica) (Fallopia aubertii, Bilderdykia aubertii, Bilderdykia balschuanicum) – Russian vine
Polygonum cilinode (Fallopia cilinodis, Bilderdykia cilinodis) – fringed black bindweed
Polygonum convolvulus (Fallopia convolvulus) – Black Bindweed, wild buckwheat
Polygonum cuspidatum = Polygonum japonicum - Japanese knotweed
Polygonum dumetorum (Fallopia dumetorum) – copse bindweed
Polygonum japonicum (Fallopia japonica, Reynoutria japonica) – Japanese knotweed
Polygonum multiflorum (Fallopia multiflora)
Polygonum sachalinense (Fallopia sachalinensis, Reynoutria sachalinensis) – giant knotweed
Polygonum scandens (Fallopia scandens)

[edit] Reclassified as Persicaria

Flowerhead of Persicaria maculata (syn. Polygonum persicara)

Polygonum affine (Persicaria affinis)
Polygonum alatum (Persicaria alata)
Polygonum alpinum – alpine knotweed (Persicaria alpina)
Polygonum amphibium – amphibious bistort, longroot smartweed, water smartweed, (Persicaria amphibia)
Polygonum amplexicaule (Persicaria amplexicaulis)
Polygonum bistorta – bistort (Persicaria bistorta)
Polygonum campanulatum – lesser knotweed, bellflower smartweed, (Persicaria campanulata) (Reynoutria campanulatum)
Polygonum capitatum - pinkhead smartweed, (Persicaria capitata)
Polygonum emodi (Persicaria emodi)
Polygonum filiforme (Persicaria virginiana)
Polygonum hydropiper – water-pepper (Persicaria hydropiper)
Polygonum lapathifolium – pale persicaria or nodding smartweed (Persicaria lapathifolia)
Polygonum longisetum (Persicaria longiseta)
Polygonum macrophyllum (Persicaria macrophylla)
Polygonum milletii (Persicaria milletii)
Polygonum minus – small water-pepper (Persicaria minor)
Polygonum mite – tasteless water-pepper (Persicaria mitis, Persicaria laxiflora)
Polygonum molle (Persicaria mollis)
Polygonum nepalense (Persicaria nepalensis)
Polygonum odoratum – Vietnamese coriander (Persicaria odorata)
Polygonum orientale (Persicaria orientalis)
Polygonum pensylvanicum – Pennsylvania smartweed or pink knotweed or pinkweed (Persicaria pensylvanica)
Polygonum persicaria – redshank or persicaria or lady's thumb (Persicaria maculosa)
Polygonum polystachyum = Polygonum wallichii
Polygonum runciforme (Persicaria runcinata)
Polygonum sagittatum – arrowleaf tearthumb, American tear-thumb or scratchgrass (Persicaria sagittata)
Polygonum tenuicaule (Persicaria tenuicaulis)
Polygonum tinctorium (Persicaria tinctoria)
Polygonum vaccinifolium (Persicaria vaccinifolia)
Polygonum virginianum (Persicaria virginiana)
Polygonum viviparum – alpine bistort (Persicaria vivipara)
Polygonum wallichii – Himalayan knotweed (Persicaria wallichii)
Polygonum weyrichii (Persicaria weyrichii)