Polygonum rurivagum

Tracheophyta MagnoliopsidaPolygonaceaePolygonumPolygonum rurivagum


An annual of arable fields and more rarely of ruderal habitats, especially on light chalky soils and calcareous clays. Lowland.



World Distribution

As an archaeophyte P. rurivagum has a European Temperate distribution.

© K.J. Walker, BSBI

Broad Habitats

Arable and horticultural (includes orchards, excludes domestic gardens)

Light (Ellenberg): 8

Moisture (Ellenberg): 4

Reaction (Ellenberg): 8

Nitrogen (Ellenberg): 5


Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 3.9

July Mean Temperature (Celsius): 16.1

Annual Precipitation (mm): 738

Life form information

Height (cm): 20

Perennation - primary


Life Form - primary

Therophyte (annual land plant)



Clonality - primary

Little or no vegetative spread

Count of 10km squares in Great Britain: 274

Count of 10km squares in Ireland: 0

Count of 10km squares in the Channel Isles: 4

Distribution information

JNCC Designations


Scarce Atlas Account

Scarce Atlas Account: 

Polygonum rurivagum Jordan ex Boreau

Cornfield knotgrass

Status: not scarce


This is a plant of arable fields on calcareous or light soils, especially on the chalk. It sometimes occurs as a ruderal and on disturbed road-verges. 

The plant is annual and usually self-pollinated. It begins to flower in late July or August, later than related species of Polygonum, continuing to flower after fields have been harvested until November.

Although there has apparently been a decline in southern and south-eastern England, the species has been recorded over a wider range in recent years. This may indicate that it has been overlooked and recent records from western Wales suggest that it should be sought more widely. Few recorders report it, but those that do seem to find it repeatedly.

The European distribution is still not fully known, but there are records for most territories in south-western to western-central Europe, northwards to Sweden and southwards to Sicily and Macedonia. Similar plants have been described from Russia, Ukraine and the Baltic Republics as P. neglectum Besser and P. scythicum Klokov.

P. rurivagum was treated as a species by Moss (1914), but not fully understood in Britain until Styles (1962) revised the P. aviculare aggregate. It is superficially very similar to P. aviculare, of which it is probably a segetal ecotype.


J. R. Akeroyd

PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.

Atlas text references

Atlas Supp (43b)
Lousley JE, Kent DH
1981.  Docks and knotweeds of the British Isles. Botanical Society of the British Isles Handbook no. 3.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.
Styles BT
1962.  The taxonomy of Polygonum aviculare and its allies in Britain. Watsonia. 5:177-214.