prostrate knotweed

(Polygonum aviculare)

Overview
prostrate knotweed
 
 

Prostrate knotweed is a very widespread and very common annual herb. Its origin is uncertain but it is thought to be native to Europe, Asia, and North America. Its spread has been greatly assisted by humans. It is now naturalized on every continent except Antarctica. It is found in bottomland forests, marshes, swamps, bottomland prairies, pastures, agricultural fields, farmyards, ditches, roadsides, railroads, lawns, and sidewalk cracks, and on banks of rivers, streams, lakes, and ponds.

     
           
 
Description
 
 

There are six subspecies of prostrate knotweed in North America, five of which occur in Minnesota. They vary greatly in appearance. However, in areas where two subspecies occur, populations with characteristics of both subspecies can be found. According to Flora of North America, this makes identification to the subspecies level impractical.

The stems are flexible, semi-erect to sprawling, and 1 to 6 long. The nodes are translucent, becoming jagged. The sap is highly acidic but clear, not milky. The leaves are green or grayish-green and variable in shape. Leaf blades may be narrowly ellipse-shaped, egg-shaped, or spatula-shaped. Flowers appear in small clusters at the leaf axils. Flowers are produced from August to October. The flowers may be green or reddish-brown, and may have white, pink, or reddish margins. The outer 3 petal-like sepals are not longer than the petals, however this is not visible without a hand lens.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 22, 28, 30.

BONAP shows this species occurring in most counties in the state. Other sources show it in far fewer counties, though all sources show it widely distributed. The map at left includes the BONAP data.

 
  3/27/2021      
         
 
Taxonomy
 
  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  
 

Order

Solanales (nightshades, bindweeds, gooseweeds, and allies)  
 

Family

Polygonaceae (buckwheat)  
  Subfamily Polygonoideae  
  Tribe Polygoneae  
  Subtribe Polygoninae  
 

Genus

Polygonum (knotweed)  
       
 

Subordinate Taxa

 
 

box knotweed (Polygonum aviculare ssp. buxiforme)

common knotweed (Polygonum aviculare ssp. aviculare)

narrow-leaf knotweed (Polygonum aviculare ssp. neglectum)

narrow-leaf knotweed (Polygonum aviculare ssp. rurivagum)

northern knotweed (Polygonum aviculare ssp. boreale)

oval-leaf knotweed (Polygonum aviculare ssp. depressum)

 
       
 

Synonyms

 
 

Polygonum aviculare var. vegetum

Polygonum heterophyllum

Polygonum monspeliense

 
       
 

Common Names

 
 

prostrate knotweed

yard knotweed

 
       

 

 

 

 

 

 

 

 

 

       
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Colony

  prostrate knotweed   prostrate knotweed
       

Plant

  prostrate knotweed    
       
       

 

Camera

     
Slideshows
   
  Polygonum aviculare
Susanne Wiik
 
  Polygonum aviculare  
 
About

Tungress, Knotgrass

 
     
  Polygonum aviculare
Matt Lavin
 
  Polygonum aviculare  
 
About

Introduced annual (and perennial) with generally prostrate stems, whitish tepals tinged with rose, common in highly disturbed settings including along sides of roads, trails, sidewalks, lawns, curbs, and similar town settings.

 
     
  Polygonum aviculare
Cristina Corral
 
   
 
About

Cristina Corral

http://www.pfaf.org/user/Plant.aspx?LatinName=Polygonum+aviculare

http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?29238

 
     

 

slideshow

       
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  Polygonum aviculare
Novenyismeret
 
   
 
About

Uploaded on Oct 8, 2008

Polygonum aviculare
(Corvinus beszámoló)

   
       
  EL CIENNUDOS: Polygonum aviculare (http://riomoros.blogspot.com.es)
Published on Sep 14, 2012
 
   
 
About

Published on Sep 14, 2012

El Ciennudos (Polygonum aviculare) es una planta herbácea anual de la familia Polygonaceae y origen en Europa.

Su desarrollo es rastrero pudiendo llegar a 1 m de longitud. Puede tomar carácter erguido en determinadas condiciones. Los tallos parten de un punto central, donde se unen a la raíz, y se extienden radialmente ramificándose. Tiene nudos y entrenudos. De los nudos salen las hojas y flores y, de algunos, salen nuevas ramas. Son de color verde oscuro grisáceo, con líneas longitudinales.

Las hojas son simples, de peciolo muy corto, de forma elíptica, con el borde liso y color verde oscuro a glauco.

Las flores son pequeñas, solitarias o en grupos pequeños, apareciendo en la axila de las hojas. Tienen la corola con cinco pétalos de color blanco a rosado.

El fruto es un aquenio.

En la naturaleza se da en zonas ruderales y campos de cultivo y barbechos. Es una buena cobertora de suelos para evitar la erosión en las etapas iniciales de restauración.

Más información sobre El Ciennudos (Polygonum aviculare) en: http://riomoros.blogspot.com/2012/10/el-ciennudos-polygonum-aviculare.html

   
       

 

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