Polygonum lapathifolium (pale persicaria)
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Polygonum lapathifolium L.
Preferred Common Name
- pale persicaria
Other Scientific Names
- Persicaria lapathifolia (L.) Gray
- Persicaria lapatitifol
- Persicaria nodosum Pers.
- Polygonum andrzejowskianum Klokov
- Polygonum brittingeri Opiz
- Polygonum hypanicum Klokov
- Polygonum incanum F. W. Schmidt
- Polygonum linicola Sutulov
- Polygonum nodosum Pers.
- Polygonum paniculatum Andrz.
- Polygonum scabrum Moench
- Polygonum tomentosum Schrank
- Polygonum zaporoviense Klokov
International Common Names
- English: pale smartweed; white smartweed
- Spanish: poligòno pata perditz
- French: renouée à feuilles de patience
- Portuguese: erva-bastarda; mal-casada
Local Common Names
- Czechoslovakia (former): rdesno blesnik
- Denmark: bleg pileurt
- Finland: ukon tatar
- Germany: Ampferblättriger Knöterich
- Hungary: lapulevelü keserüfü
- Italy: Persicaria maggiore
- Japan: sanaetade
- Lebanon: ghadar; hummayadh
- Netherlands: viltige duizendknoop
- Poland: rdest szczawiolistny
- Slovakia: horciak stiavolistý
- Sweden: pilört
- POLLA (Polygonum lapathifolium)
- POLSC (Polygonum scabrum)
- POLTO (Polygonum tomentosum)
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Polygonales
- Family: Polygonaceae
- Genus: Polygonum
- Species: Polygonum lapathifolium
Notes on Taxonomy and NomenclatureTop of page P. lapathifolium L. is the most commonly accepted name for this widespread and variable species. However, P. lapathifolium normally reproduces autogamously and this has led to the production of numerous pure lines, many of which are locally constant and have been named as species or subspecies. One of these is P. nodosum Pers., with glabrous leaves, yellow foliar glands, and pink flowers in a rather lax spike, characteristic of river gravels in some regions. Similarly, P. tomentosum Schrank, which has a low habit, densely tomentose leaves and greenish-white flowers, is often seen. Tutin et al. (1961) conclude that since these characteristics are not as perfectly developed in some plants as in others, they should not be assigned taxonomic rank.
Consaul and McNeil (1986) describe a similar problem of differentiation between species identified as P. lapathifolium and P. scabrum in North America. The variants differ biologically in speed of germination and flowering, and phenotypically in inflorescence and leaf characteristics. However, identification problems exist for about 5% of individuals in the field and a somewhat greater percentage in herbarium material. Multivariate analysis of fruit characteristics showed clear differences between the two taxa. However electrophoretic study of 15 enzymes, showed that 17 of the 22 loci resolved showed absolutely no variation. Only leucine aminopeptidase revealed allozymes characteristic for the two taxa.
In contrast, Tutin et al. (1961) also describe P. brittingeri Opiz., with procumbent much-branched stems and very short internodes, broadly elliptical or ovate leaves, densely tomentose beneath with colourless glands. These characteristics are retained in cultivation and P. brittingeri shows a well-defined geographical distribution in the river basins of the Upper Danube and Rhine. Because of this, the authors feel this variant should merit recognition either as a species or as a subspecies.
DescriptionTop of page P. lapathifolium is a branched, erect, herbaceous, annual plant growing to 100 cm but rarely exceeding 50 cm. The species is very plastic phenotypically especially in flower colour and pubescence (Tutin et al., 1961; Stace, 1991). The cotyledons are slender, length three times the width, usually with a reddish hypocotyl. The stems are swollen above the nodes and usually green, distinguishing the species from the closely related P. persicaria whose stems are purple. The leaf stipules or ochreae are fused into a tube, truncate with only the uppermost very shortly fringed. The leaves are alternate, 5-20 cm long, with a short petiole and sunken pellucid resinous glands on the underside. Leaf shape is elliptical-lanceolate with regularly arranged hairs projecting from the margin, and sometimes woolly beneath, but coarsely hairy on the midrib, which often has black blotches. The flowers are greenish-white, rarely pink, with sparsely glandular perianth segments and peduncles. The inflorescences are erect cylindrical, terminal or axillary. Seeds are 2.5-3 mm, shiny, flattened, biconcave and triangular in section.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Afghanistan||Widespread||Holm et al., 1979|
|Azerbaijan||Widespread||TUTIN and ET, 1964|
|China||Widespread||Holm et al., 1979|
|Georgia (Republic of)||Widespread||GRIN, 1999|
|Indonesia||Present||Holm et al., 1979|
|Iran||Present||Holm et al., 1979|
|Iraq||Widespread||Holm et al., 1979|
|Japan||Widespread||Holm et al., 1979|
|Jordan||Present||Holm et al., 1979|
|Korea, DPR||Widespread||Holm et al., 1979|
|Korea, Republic of||Widespread||Holm et al., 1979|
|Lebanon||Widespread||Holm et al., 1979|
|Pakistan||Present||Holm et al., 1979|
|-Russia (Asia)||Widespread||TUTIN and ET, 1964|
|Syria||Widespread||TUTIN and ET, 1964|
|Taiwan||Present||Holm et al., 1979|
|Thailand||Present||Holm et al., 1979|
|Turkey||Present||Demirci and Gene, 2009|
|Tunisia||Widespread||Holm et al., 1979|
|Canada||Widespread||Holm et al., 1979|
|Mexico||Present||Ríos et al., 2004|
|USA||Present||Holm et al., 1979|
|-California||Present||Naylor et al., 2005|
|-Illinois||Present||Olszyk et al., 2008|
|-Minnesota||Present||Perry and Galatowitsch, 2003|
|-Mississippi||Present||Reinecke and Hartke, 2005|
|-North Carolina||Present||Askew and Wilcut, 2002|
|-Ohio||Present||Jiang et al., 2008|
|-Oklahoma||Present||Takasaki et al., 2001|
|Argentina||Present||Holm et al., 1979|
|Brazil||Present||Pitelli et al., 2009|
|-Rio de Janeiro||Present||Pitelli et al., 2009|
|-Sao Paulo||Present||Martins et al., 2008|
|Chile||Present||Holm et al., 1979|
|Albania||Widespread||TUTIN and ET, 1964|
|Austria||Widespread||Holm et al., 1979|
|Belarus||Widespread||TUTIN and ET, 1964|
|Belgium||Widespread||Holm et al., 1979|
|Bulgaria||Widespread||Tutin et al., 1980|
|Croatia||Widespread||TUTIN and ET, 1964|
|Czech Republic||Present||Smutný and Kren, 2003|
|Czechoslovakia (former)||Widespread||TUTIN and ET, 1964|
|Denmark||Widespread||TUTIN and ET, 1964|
|Estonia||Present||Lauringson et al., 2000|
|Finland||Widespread||Holm et al., 1979|
|France||Widespread||TUTIN and ET, 1964|
|-Corsica||Widespread||TUTIN and ET, 1964|
|Germany||Widespread||Holm et al., 1979|
|Greece||Widespread||TUTIN and ET, 1964|
|Hungary||Widespread||Holm et al., 1979|
|Iceland||Present||Holm et al., 1979|
|Ireland||Widespread||TUTIN and ET, 1964|
|Italy||Widespread||TUTIN and ET, 1964|
|Netherlands||Widespread||Holm et al., 1979|
|Norway||Widespread||Holm et al., 1979|
|Poland||Widespread||Holm et al., 1979|
|Portugal||Widespread||Holm et al., 1979|
|-Azores||Widespread||TUTIN and ET, 1964|
|Romania||Widespread||TUTIN and ET, 1964|
|Russian Federation||Widespread||Holm et al., 1979|
|-Russia (Europe)||Widespread||TUTIN and ET, 1964|
|-Russian Far East||Widespread||TUTIN and ET, 1964|
|Spain||Widespread||Holm et al., 1979|
|-Balearic Islands||Widespread||TUTIN and ET, 1964|
|Sweden||Widespread||Holm et al., 1979|
|Switzerland||Widespread||TUTIN and ET, 1964|
|UK||Widespread||TUTIN and ET, 1964; Holm et al., 1979; GRIN, 1999|
|Yugoslavia (Serbia and Montenegro)||Widespread||Holm et al., 1979|
|Australia||Widespread||Holm et al., 1979|
|New Zealand||Widespread||Holm et al., 1979|
HabitatTop of page The Polygonum genus is cosmopolitan, particularly so in temperate regions. It consists of about 175 species, among which a number of hybrids, bearing characters intermediate between those of the parents, have been recorded. P. lapathifolium is found throughout the temperate regions of the northern hemisphere and in South Africa. It is a weedy species found in waste places, cultivated ground, ditches and damp areas beside water. It is particularly abundant on nutrient rich, friable soils and organic fen soils.
Although P. lapathifolium occurs in flooded to moderately dry conditions and in poor as well as rich soils, it does not tolerate such wide moisture and nutrient ranges, or such a range of soil temperatures, as P. persicaria. P. lapathifolium is also less tolerant of shade than other weedy species of Polygonum.
Hosts/Species AffectedTop of page P. lapathifolium is likely to occur as a troublesome weed in virtually every spring-sown crop of temperate regions. Because of its relative intolerance of shady conditions it is likely to be most troublesome during crop establishment and in row crops such as maize, soyabean and sugarbeet that admit plenty of light for some time after emergence.
Biology and EcologyTop of page P. lapathifolium has a pronounced weedy habit and spreads entirely by seed. It produces 800-850 seeds per plant which, in common with other species of Polygonum, germinate mainly in the spring. A study in Japan (Watanabe, 1978) has shown that seeds of P. lapathifolium have a chilling requirement to break dormancy, with an optimum temperature of 1-5°C. Seed longevity is variable. Klemm (1988) has shown that P. lapathifolium seeds germinated at a rate of 10% after 10-11 years storage, while those stored for 6 years were 90% viable. However, in a controlled experiment Japan in which 200 seeds were mixed with sterilized soil, buried in plastic cylinders and recovered periodically for 4 years to determine viability, seeds of P. lapathifolium showed over 10% emergence after 2 years but mostly lost viability after 4 years (Takabayashi and Nakayama, 1978).
In common with P. persicaria, P. lapathifolium can maintain a high photosynthetic performance in a variety of moisture and nutrient environments (Sultan et al., 1998a), but it is less tolerant of shade, particularly early in the growth season (Sultan et al., 1998b). It is, therefore, more limited in scope than P. persicaria, but potentially a problem weed in any spring sown temperate crop especially when it emerges with or before the crop.
A move away from traditional seedbed preparation to zero cultivation (no tillage) to achieve earlier sowing will encourage P. lapathifolium. Elmore and Heatherly (1983) compared sowing soyabeans in stale and conventional seedbeds for 2 years at two locations in the Mississippi River alluvial plain and demonstrated that the absence of pre-plant tillage led to the presence of early summer germinating annuals, including P. lapathifolium.
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
ImpactTop of page Because of its widespread distribution and weedy habit, P. lapathifolium is potentially a damaging weed in any spring-sown crop where it occurs. However, the relative intolerance of shade compared with other species of Polygonum means that it is likely to have greater impact as a weed in newly sown, establishing crops than in established perennial crops. Sieberhein et al. (1983) demonstrated this to be the case in a study of the major weeds infesting new and established lucerne stands in 68 trials at 16 sites in Germany in 1971-82. In a detailed study on sugarbeet Watanabe and Hirokawa (1975) found that an infestation of 18 plants of P. lapathifolium/m² in sugarbeet reduced yield by 81%.
In addition to competitive effects, P. lapathifolium hosts a number of damaging pests. Reports include beet western yellows virus and potato leaf roll virus in British Columbia, Canada (Ellis, 1992); cucumber mosaic virus (Dikova, 1989); eriophid mites (Petanovic et al., 1893); spinach wilt virus (Fusarium oxysporum) (Naiki and Morita, 1983); Rhizoctonia solani (Krylova, 1981); Meloidoderita in Maryland, USA (Andrews et al., 1977); cutworms (Agrotis ipsilon) (Anon., 1977); and onion stem nematode (Gentzsch, 1973).
UsesTop of page P. lapathifolium is extensively used as an insecticide in Bangladesh. Ahmed et al. (1990) found, in addition to several known chalcones, a new isoflavanone, a dihydrochalcone and three chalcone derivatives. The structures of the compounds were determined by high field 1H NMR and other spectroscopic techniques. In other work (Tahara et al., 1993), P. lapathifolium has been found to be a source of several naturally occurring benzimidazole antidotes, including three phenolics, 3,5-dihydroxy-4-methylstilbene and 5-methoxy-6,7-methylenedioxyflavone.
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
The annual habit of P. lapathifolium and the fact that it reproduces entirely by seed, all of which germinate in the spring and early summer, means that normal seedbed cultivation and 'stale seedbed' techniques can achieve some measure of control before the crop is sown. However, the number of seedlings produced can be very high and many will emerge with the growing crop. In wide row crops mechanical or manual hoeing can control the weed between the rows, but heavy infestations will almost always need additional chemical treatment.
Because of the widespread occurrence of P. lapathifolium as a weed of temperate crops, many different herbicides are used against it in different crops and in different territories. The following list, compiled mainly from Fryer and Makepeace (1978), lists susceptibility to most commonly used herbicides:
Soil applied: P. lapathifolium is susceptible to ametryn, bromacil, chlorbromuron, chloridazon, chlorpropham, cyanazine, cycloate, ethofumesate, lenacil, linuron, metribuzin, monolinuron, nitrofen, propham, terbacil, trietazine and trifluralin; moderately susceptible to atrazine, chloroxuron, metamitron, metobromuron and simazine; and resistant to isoproturon.
Foliar applied: P. lapathifolium is susceptible to ametryn, bentazone, bromoxynil, chlorbromuron, cyanazine, dicamba, ioxynil, linuron, metamitron, metribuzin, metsulfuron-methyl, monolinuron, prometryn, sodium monochoracetate and thifensulfuron-methyl; moderately susceptible to diflufenican and ethofumesate; and resistant to 2,4-D, 2,4-DB, 2,4-DP, MCPA, MCPB and mecoprop.
In addition, there are numerous records of successful control of P. lapathifolium in the literature. These include: acetochlor, dimethenamid and metolachlor on sweetcorn (Miller and Libbey, 1999); aclonifen on peas (Kloster, 1999) and sunflowers (Rapparini, 1996); atrazine, cyanazine and metolachlor on maize (Djurkic and Knezevic, 1993); butylate, cyanazine, EPTC, metolachlor, vernolate on maize (Rapparini, 1986); bentazone, linuron, metobromuron, metolachlor and prometryn on soyabean (Skender and Vrataric, 1986); bentazone and EPTC on Galega orientalis (Kutuzov and Shagarov, 1986); bentazone on barley (Shalna and Melamed, 1986); bentazone on flax (Ryzhaya et al., 1984); buthidazole, dimethachlor and fluridone on sugarbeet (May, 1979); chloridazon, cycloate and lenacil on sugarbeet (Satarov, 1987); chloridazon, metamitron, metolachlor and phenmedipham on sugarbeet (Domanska et al., 1984); chloridazon, lenacil and phenmedipham on oat (Natal'ina and Svetov, 1973); choridazon, ethofumesate, lenacil and phenmedipham on sugarbeet (Fisher, 1992); dicamba, methoprotryne and simazine on oat (Beshanov and Adigezalov, 1975); ethalfluralin, hexazinone and oxyfluorfen (glasshouse) (May, 1978); fluoroglycofen-ethyl on spring barley (Petunova, 1995); fluroxypyr (glasshouse) (Mikulka, 1987); imazaquin, pendimethalin, trifluralin and vernolate on soyabean (Godec and Opacic, 1988); metamitron and phenmedipham on fodder beet (van Himme et al., 1986); metolachlor and metribuzin on potato (Laszlo, 1986); metolachlor on maize (Zuza, 1983); rimsulfuron on maize (Djurkic et al., 1997); sulcotrione on maize (Compagnon and Beraud, 1996); and triflusulfuron on sugarbeet (Simoneit, 1992).
In general P. lapathifolium is susceptible to most classes of herbicide, with the notable exception of the aryloxyalkanoic acids. It was not until the appearance of the benzoic acid derivatives (for example, dicamba) that effective chemical control of Polygonum in cereals became possible. The substituted urea herbicides are mostly only moderately active, and isoproturon gives very little control.
P. lapathifolium is one of a number of species now exhibiting chloroplastic resistance to triazine herbicides as a result of intensive use of this group of herbicides in maize, vineyards and for industrial weed control. Resistance in P. lapathifolium was first found in Europe in France in 1978, followed by Germany (1986), former Czechoslovakia and the Netherlands (1988) (LeBaron, 1991). Mikulka et al. (1988) found large populations of the resistant biotype at several railway stations in former Czechoslovakia. Van Oorschot (1991) has reviewed the occurrence of triazine resistance in P. lapathifolium and other weed species in Europe and reports its presence in Italy in addition to the countries mentioned above. Rapparini (1986) reports resistance in the USA.
Atrazine inhibits the Hill Reaction in susceptible biotypes. The resistance mechanism is a reduced affinity for atrazine at its target site. Prado et al. (1995) demonstrated a 35.5-fold greater resistance in the R biotype of P. lapathifolium from seeds collected in Spain. Darmency and Gasquez (1982) found that the chloroplasts from resistant biotypes required less energy for activation, suggesting that these variants may also be more tolerant of low temperatures. Furthermore, Gasquez et al. (1981) suggested that they may also germinate more readily at low temperatures. To complicate matters, Barralis et al. (1979) found that in field trials, plants resistant to atrazine showed some degree of resistance to other herbicides tested.
ReferencesTop of page
Anon., 1995. Weeds in Sugar Beet. Berlin, Germany: Hoechst Schering AgrEvo GmbH.
Barralis G, Gasquez J, Jan P, Soffietti S, 1979. Physiological and ecological behaviour of broad-leaved weeds resistant to atrazine in France. Proceedings EWRS Symposium on the Influence of Different Factors on the Development and Control of Weeds, Mainz, 1979., 217-224
Brendstrup I, 1998. Fenix (aclonifen) - a novel herbicide for use in carrot, parsley (parsley root), parsnip, celery, set onion, green peas and potatoes. In: Proceedings 15th Danish Plant Protection Conference - Pests and Diseases: Danmarks JordbrugsForskning, Tjele, Denmark, 3:239-248
Clapham AR, Tutin TG, Warburg EF, eds, 1952. Flora of the British Isles. Cambridge, UK: Cambridge University Press
Compagnon JM, Beraud JM, 1995. Use of sulcotrione alone or in combination for the resolution of regional problems of weed control in maize. In: COLUMA, eds. Proceedings SeiziFme conférence du COLUMA - Journées internationales sur la lutte contre les mauvaises herbes, Reims, France: Association Nationale pour la Protection des Plantes (ANPP), Paris, France, 2, 805-812
Darmency H, Gasquez J, 1982. Differential temperature-dependence of the Hill activity of isolated chloroplasts from triazine resistant and susceptible biotypes of Polygonum lapathifolium L. Plant Science Letters, 24(1):39-44
Elmore CD, Heatherly LG, 1983. Weed hosts of beet western yellows virus and potato leafroll virus in British Columbia. Abstracts, 1983 Meeting of the Weed Science Society of America, 66-67
Fryer JD, Makepeace RJ, eds, 1978. Weed Control Handbook, Volume II/Recommendations. 8th edn. Oxford, UK: Blackwell Scientific Publications
Gentzsch D, 1973. Die Vermehrung des Zwiebeln schadigenden Stengelnematoden (Ditylenchus dipsaci) in Unkrautern und Schlussfolgerungen fur den Herbizideinsatz. (The increase of the onion stem nematode (Ditylenchus dipsaci) in weeds and implications for herbicide application). Vortrage der 12. Tagung uber Probleme der Phytonematologie, Gross Lusewitz, 1. Juni 1973, 109-120
GRIN, 1999. GRIN taxonomy. Agricultural Research Service, Washington, USA. World Wide Web page at http://www.ars.grin.gov/
Jiang LJ, Koch T, Dami I, Doohan D, 2008. The effect of herbicides and cultural practices on weed communities in vineyards: an Ohio survey. Weed Technology, 22(1):91-96. http://wssa.allenpress.com/perlserv/?request=get-abstract&doi=10.1614%2FWT-07-100.1
Kloster I, 1999. For weed control in peas your choice should be Fenix. In: 16th Danish plant protection conference: Side effects of pesticides, weeds: Danmarks JordbrugsForskning Tjele, Denmark, 9:197-202
LeBaron HM, 1991. Distribution and seriousness of herbicide resistant weed infestations worldwide. In: Caseley JC, Cussans GW, Atkins RK, eds. Herbicide Resistance in Weeds and Crops. Oxfor, UK: Butterworth, 27-43
Martins D, Costa NV, Terra MA, Marchi SR, 2008. Characterization of the aquatic plant communities of 18 reservoirs of five watersheds in Sao Paulo, Brazil. (Caracterização da comunidade de plantas aquáticas de dezoito reservatórios pertencentes a cinco bacias hidrográficas do estado de São Paulo.) Planta Daninha, 26(1):17-32. http://www.scielo.br/pd
May MJ, 1978. Glasshouse investigations with newer soil-applied herbicides for weed control on organic soils. Proceedings 1978 British Crop Protection Conference - Weeds. British Crop Protection Council. London UK, 777-784
Miller TW, Libbey CR, 1999. Response of three sweet corn cultivars to several herbicides. Research Progress Report, Western Society of Weed Science, Colorado Springs, Colorado, USA, 1999, 57-58
Naiki T, Morita Y, 1983. Isolation of spinach wilt fungus, Fusarium oxysporum f.sp. spinaciae, from weed roots grown in fields. Annals of the Phytopathological Society of Japan, 49(4):573-575; [1 tab.]; 10 ref
Naylor LW, Eadie JM, Smith WD, Eichholz M, Gray MJ, 2005. A simple method to predict seed yield in moist-soil habitats. Wildlife Society Bulletin, 33(4):1335-1341. http://www.wildlife.org/publications/index.cfm?tname=bulletin
Olszyk D, Pfleeger T, Lee EH, Burdick C, King G, Plocher M, Kern J, 2008. Selecting and evaluating native plants for region-specific phytotoxicity testing. Integrated Environmental Assessment and Management (IEAM), 4(1):105-117. http://entc.allenpress.com
Oorschot JLP van, 1991. Chloroplastic resistance of weeds to triazines in Europe. In: Caseley JC, Cussans GW, Atkin RK, eds. Herbicide Resistance in Weeds and Crops. Oxford, UK: Butterworth-Heinemann, 87-101
Petunova AA, 1995. Controlling weeds resistant to 2,4-D in Russian cereal crops. Resistant Pest Management, 7(2):23
Pitelli RLCM, Ferraudo AS, Pitelli AMCM, Pitelli RA, Velini ED, 2009. Using multivariate statistics and artificial neural networks to determine the colonization behavior of aquatic macrophyte populations in Santana reservoir. (Utilização de análise multivariada e redes neurais artificiais na determinação do comportamento de colonização de populações de macrófitas aquáticas no reservatório de-Santana.) Planta Daninha, 27(3):429-439. http://www.scielo.br/pd
Ríos Torres A, Osuna García JA, López Arriaga G, 2004. Ecological survey of weeds in the tobacco growing area of Rosamorada, Nayarit. (Levantamiento ecologico de maleza en la zona tabacalera de Rosamorada, Nayarit.) In: Memoria XVI Congreso Latinoamericano de Malezas y XXIV Congreso Nacional de la Asociación Mexicana de la Ciencia de la Maleza, Manzanillo, Colima, México, del 10 al 12 de Noviembre de 2003 [ed. by Pedrero, G. M.\Valenzuela, J. A. D.\Díaz, G. M.\Ruiz, R. A. O.]. Wimauma, USA: Asociación Latinoamericana de Malezas, 311-316. http://gcrec.ifas.ufl.edu/Weed%20Science/ALAM/Web%20page/ALAM01.htm
Stace C, 1991. New Flora of the British Isles. Cambridge, UK: Cambridge University Press
Sultan SE, Wilczek AM, Bell DL, Hand G, 1998. Contrasting ecological breadth of co-occurring annual Polygonum species. Journal of Ecology, Oxford, 86(3):363-383
Takabayashi M, Nakayama K, 1978. The seasonal change in seed dormancy of main upland weeds. Weed Research, Japan, 23(1):32-36
Distribution MapsTop of page
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