Plant Image
Flower spike


Yavapai County Native & Naturalized Plants

Polygonum amphibium - water knotweed

Other Common Names: water smartweed
Plant Form: Forb or Subshrub

Family: Polygonaceae


   
 
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Plants
Max Licher @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
Forb Plant Description

Origin: Native   Life Cycle: Perennial
General Desc: Freely rooting from rhizomes, long, prostrate stems growing across mud or in water and topped with erect, dense, narrowly egg-shaped, pink flower clusters.
Identification notes: Rhizomatous perennial, aquatic or amphibious or terrestrial. Stems not twining. Leaves basal and alike, elliptic or rounded, not jointed with the stipule sheath. Spike-like flower heads of pink flowers are short and thick, terminal or nearly so.
Height: Stems 3 to 6 feet


Habitat

Habitat Description: Marshes, ponds and lakes.
Plant Communities: Riparian
Elevation: 5000 - 9000 feet


Flower Characteristics

Color: Deep pink     Shape: Regular in elongated clusters     Tubular: Y     Flowering Period: Jun - Sep
Description: Individual flowers are tiny, less than 1/4 inch wide and 3/16 inch long, and form a slender, 2 inch long, terminal cluster. Tepals (sepals and petals) 5, bluntly rounded above, united below.


Leaf and Stem Characteristics

Leaf Color: Dark green     Leaf Type: Simple     Leaf Shape: Round or oval     Leaf Margin: Smooth     Leaf Attachment: Alternate     Leaves Clasp: N
Hairs: No     Spines: N
Leaf Description: Leaves are shiny and leathery; mainly floating; 6 inches long.


Fruit and Seed Characteristics

No Fruit or seed notes


  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 8.0  
http://cales.arizona.edu/yavapaiplants/SpeciesDetailForb.php  
Last Updated: Dec 13, 2022
Content Questions/Comments: Email Matt Halldorson  
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