by Stephen Mifsud
   10 Dec 2023      ()
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Polygonum equisetiforme   (Horsetail Knotweed)

Polygonum equisetiforme  (POLYGONACEAE.) 
Images for this profile are taken from the Maltese Islands after year 2000.

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Profile Date Aug-2022 (taxon update: none)
Citation for this page Mifsud, S. (2022). Polygonum equisetiforme - datasheet created on Aug-2022. Retrieved from on 10-Dec-2023

Nomenclature and Basic Information

Species name :

Polygonum equisetiformeSm.
Published in Fl. Graec. Prodr. 1: 269 (1809)

Synonyms :
(basionym or principal syn.)

No Main Synonyms

Plant Family :

Polygonaceae Juss. (The Dock Family)
24 species from the Polygonaceae family are recorded from the Maltese Islands.

English name(s) :

Horsetail Knotweed

Maltese name(s) :

Lewża ta' skarsa

Status for Malta :

Indigenous. Present on the Maltese islands before man

Frequency :

Very Common     Common    Frequent     Scarce     Rare    Very rare     Extinct in the wild

Growth form :

Raunkiaer lifeform [info]: HEMICRYPTOPHYTE ( prostate plants with flowers close to the ground )
Germination [info]: Dicotyledon

Legal Protection :

Not legally protected till the last update of this website (2/Mar/2022)

Red List (1989) :

Threatened status for the Maltese Islands and has been listed in the Red Data Book (1st ed.)

Flowering Time :

June – October

Colour of Flowers:

White or Inconspicuous


Not particularly toxic

Name Derivation :

Polygonum: "Derived from the Greek words ""poly"", meaning many and ""gonu"", meaning knee or joint and hence ""many joints"" because many species of this Genus have numerous thickened joints at the stems.". (Greek origin )

Planting in rural areas :

Can be planted in rural areas according to ERA Guidelines

Remarks :

Extinct in the wild but one or a few specimen exist in botanic gardens.

Description, Habitat and Distribution
Habitat in Europe: Chiefly ruderal.
Preferred habitat in Malta: Data will be available in the next update of this website.
Botanical Description: Perennial with a branched, woody stock. Stems 30-100 cm, procumbent or ascending, usually branched. Leaves 2-4 cm, oblong to linear, acute, with wrinkled margins, the lower often caducous. Ochreae hyaline, brownish towards the base, much shorter than the internodes. Flowers pink or white, in axillary clusters of 2-3, forming long, usually lax, terminal spikes; bracts herbaceous, equalling or slightly exceeding the flowers but much smaller than the lower leaves. Perianth 2.5-4 mm; styles 2-3. Nut 2-2.5 mm, glossy.
Chromosome number: 2n=20
Distributional range: S. Europe local.

Distributional map in Europe
and the Mediterranean region (2018):
Occurrences in Europe.
(from Flora Europaea pre year 1993):
the Azores, Bulgaria, Crete, Greece, Spain (incl. Andorra but excl. the Balaerics), Portugal, Sicily and/or Malta, Turkey (European part)
Occurrences in Europe and the Mediterranean region.
(from Euro+Med Checklist, 2019)
  Country codes  
AE Ag Az Bl(M) Bu Ca(C) Cr Cy Eg Gg(G) Gr Hs(G S) Ir It Jo Le Li Lu Ma -Sa ?Si(S) Sn Sy Tn Tu(A E) [nAz Az(T) aIt]

Links & Further literature (0 papers)

Google Web

Google Images

Google Scholar

Research Gate




Med Checklist

Cat. of Life



World Flora Online

Plants of the World Online

Vienna Virt. Herb.

RBGE Herbarium

KEW Herbarium




Kindly Email if there are papers and publications about local studies or information about this species to be included in the list above.

Species Images (6 images)
   Polygonum equisetiforme   -   Image Code: PLYEQ-0.
   Polygonum equisetiforme   -   Image Code: PLYEQ-1.
   Polygonum equisetiforme   -   Image Code: PLYEQ-2.
   Polygonum equisetiforme   -   Image Code: PLYEQ-3.
   Polygonum equisetiforme   -   Image Code: PLYEQ-4.
   Polygonum equisetiforme   -   Image Code: PLYEQ-5.

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Section B:   Where have you seen this plant on the Maltese Islands?
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