Polygonum

Common knotgrass Polygonum aviculare, copyright Dalgial.

Belongs within: Polygonaceae.
Contains: Polygonum sect. Persicaria, Polygonum sect. Aconogonon, Polygonum sect. Bistorta.

Polygonum, the knotweeds, is a cosmopolitan genus of herbs, shrubs and vines most diverse in northern temperate regions. Leaves are generally petioled and between 5 to 35 cm long in members of the subgenus Persicaria whereas they are more or less sessile and less than five centimetres long in species of the subgenus Polygonum (Hickman 1993).

Characters (from Hickman 1993): Annual, perennial, shrub or vine. Stem prostrate to erect, or climbing, or floating, <3 m. Leaves generally cauline, alternate, sessile or petioled, stipules fused, sheathing stem above nodes, generally scarious or membranous; blade sometimes obviously jointed to stipule sheath. Inflorescence unit a 1–8-flowered cluster, these arrayed singly or in head-like to open panicles. Flower with perianth lobes generally 5; stamens 3–8, filaments generally wider at base. Fruit generally ovoid, 3-angled, sometimes round, flat, indented; shiny to dull, brown to black.

<==Polygonum Linnaeus 1753 A61
    |--P. subg. Polygonum H93
    |    |  i. s.: P. bolanderi H93
    |    |         P. paronychia H93
    |    |         P. shastense H93
    |    |--P. sect. Polygonum H93
    |    |    |--P. arenastrum [incl. P. montereyense] H93
    |    |    |--P. argyrocoleon H93
    |    |    |--P. aviculare H93
    |    |    |--P. marinense H93
    |    |    |--P. patulum H93
    |    |    |--P. prolificum H93
    |    |    |--P. ramosissimum H93
    |    |    `--P. robertii H93
    |    |--P. sect. Duravia H93
    |    |    |--P. bidwelliae H93
    |    |    |--P. californicum H93
    |    |    `--P. parryi H93
    |    `--P. sect. Monticola non Monticola Soares 1944 (ICZN) nec Boie 1822 (ICZN) nec Nalivkin 1930 (ICZN) H93
    |         |--P. douglasii H93
    |         |    |--P. d. ssp. douglasii [incl. P. douglasii var. latifolium] H93
    |         |    |--P. d. ssp. austiniae H93
    |         |    |--P. d. ssp. johnstonii [incl. P. sawatchense] H93
    |         |    |--P. d. ssp. majus H93
    |         |    `--P. d. ssp. spergulariiforme H93
    |         |--P. minimum H93
    |         `--P. polygaloides H93
    |              |--P. p. ssp. polygaloides H93
    |              |--P. p. ssp. confertiflorum H93
    |              |--P. p. ssp. esotericum H93
    |              `--P. p. ssp. kelloggii H93
    `--P. subg. Persicaria H93
         |  i. s.: P. barbatum Linnaeus 1753 H78 [=Persicaria barbata LK14]
         |         ‘Persicaria’ bistorta V09
         |         P. chinense Linnaeus 1753 H78 [=Persicaria chinensis D07]
         |         P. glabrum VB02 [=Persicaria glabra K10]
         |         ‘Persicaria’ glacialis O88
         |         P. nepalense Meissn. 1826 H78 (see below for synonymy)
         |         ‘Persicaria’ odorata H90
         |--P. sect. Persicaria H93
         |--P. sect. Aconogonon H93
         |--P. sect. Bistorta H93
         `--P. (sect. Cephalophilon) capitatum H93 [=Persicaria capitata H90]

Polygonum incertae sedis:
  P. acuminatum H70
  P. benguetense Merr. 1915 H78
  P. chilense D03
  P. cumingianum [incl. P. celebicum] H78
  P. dumetorum C55
  P. emarginatum C55
  P. fagopyrum C55
  P. longisetum DeBr. in Miq. 1854 H78
  P. maritimum C55
  P. minus Huds. 1762 H78
  P. paniculatum [incl. P. polyanthos] H78
  P. perfoliatum Linnaeus 1762 H78
  P. plebeium [incl. P. aviculare var. dryandri] C06
    |--P. p. var. plebeium PP07
    `--P. p. var. indica PP07
  P. pubescens H78
  P. runcinatum Don 1825 H78
  P. salicifolium BG96
  P. senegalense GC05
  P. serrulatum A27
  P. sieboldi F92
  P. tataricum C55
  P. thunbergi F92
  P. viviparum CS77

Polygonum nepalense Meissn. 1826 H78 [=Persicaria nepalensis O88; incl. P. alatum Buch.-Ham. ex Spreng. 1827 H78, P. microcephalum var. papuanum Warb. 1893 H78]

*Type species of generic name indicated

REFERENCES

[A61] Allan, H. H. 1961. Flora of New Zealand vol. 1. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. R. E. Owen, Government Printer: Wellington (New Zealand).

[A27] Andersen, J. C. 1927. Popular names of New Zealand plants. Part 2. Transactions and Proceedings of the New Zealand Institute 57: 905–977.

[BG96] Baka, Z. A., & H. B. Gjaerum. 1996. Egyptian Uredinales. 1. Rusts on wild plants from the Nile Delta. Mycotaxon 60: 291–303.

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[CS77] Cramp, S., & K. E. L. Simmons (eds) 1977. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palaearctic vol. 1. Ostrich to Ducks. Oxford University Press: Oxford.

[D07] Dash, S. S. 2007. Useful plants of Kabi Sacred Grove, Sikkim. Bulletin of the Botanical Survey of India 49: 79–88.

[D03] Dusén, P. 1903. The vegetation of western Patagonia. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany pp. 1–34. The University: Princeton (New Jersey).

[F92] Fan Z. 1992. Key to the Common Flies of China 2^nd ed. Science Press: Beijing.

[GC05] Granjon, L., J.-F. Cosson, E. Quesseveur & B. Sicard. 2005. Population dynamics of the multimammate rat Mastomys huberti in an annually flooded agricultural region of central Mali. Journal of Mammalogy 86 (5): 997–1008.

[H70] Hammer, M. 1970. A few oribatid mites from Easter Island. Pacific Insects 12 (2): 279–289.

[H90] Harden, G. J. (ed.) 1990. Flora of New South Wales vol. 1. New South Wales University Press.

[H78] Henty, E. E. 1978. Polygonaceae. In: Womersley, J. S. (ed.) Handbooks of the Flora of Papua New Guinea vol. 1 pp. 222–248. Melbourne University Press: Carlton South (Australia).

[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).

[K10] Keighery, G. 2010. The naturalised vascular plants of the Pilbara region, Western Australia. Records of the Western Australian Museum Supplement 78 (1): 299–311.

[LK14] Lyons, M. N., G. J. Keighery, L. A. Gibson & T. Handasyde. 2014. Flora and vegetation communities of selected islands off the Kimberley coast of Western Australia. Records of the Western Australian Museum Supplement 81: 205–244.

[O88] Ohba, H. 1988. The alpine flora of the Nepal Himalayas: an introductory note. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 19–46.

[PP07] Pandey, R. P., & P. M. Padhye. 2007. Studies on phytodiversity of Arid Machia Safari Park-Kailana in Jodhpur (Rajasthan). Bulletin of the Botanical Survey of India 49: 15–78.

[V09] Verdcourt, B. (ed.) 2009. Additions to the wild fauna and flora of the Royal Botanic Gardens, Kew. XXVI. Miscellaneous records. Kew Bulletin 64 (1): 183–194.

[VB02] Vijay, S. K., & T. N. Bhardwaja. 2002. Vegetation and phenodynamics of wetlands of central Rajasthan. Journal of the Bombay Natural History Society 99 (3): 573–581.

Last updated: 1 January 2021.