Plant Image
Flowers and fruit


Yavapai County Native & Naturalized Plants

Polygonum ramosissimum - bushy knotweed

Synonyms: Cnopos ramosissimum, Polygonum atlanticum, P. exsertum, P. interior, P.latum, P. leptocarpum, P. patulum, P. stevensii, P.triangulum
Other Common Names: yellow flower knotweed, tall knotweed, yellow knotweed
Plant Form: Forb or Subshrub

Family: Polygonaceae


   
 
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Leaves
William Thomas @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
Plant
William Thomas @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
Forb Plant Description

Origin: Native   Life Cycle: Annual
General Desc: Annual with mostly erect stems; often much branched above with yellowish-green or bluish-green foliage. Narrow leaves have jagged brown sheaths at their bases. Small clusters of greenish or yellowish flowers grow at the leaf bases on a spike-like stalk.
Identification notes: Stems mostly erect; leaves erect, narrow, reduced upward, tip pointed, sheath at base; flowers in small spike-like clusters scattered along stems at leaf bases, petals, sepals greenish, yellowish, margins greenish-yellow or yellow, rarely pink or white.
Height: To about 3 feet


Habitat

Habitat Description: Usually moist habitats. Sometimes found in saline areas or coastal marshes but more widespread inland.
Plant Communities: Riparian
Elevation: 5000 - 7000 feet


Flower Characteristics

Color: Greenish, yellowish, rarely pink or white     Shape: Regular in elongated clusters     Tubular: N     Flowering Period: Jul - Sep
Description: 2 to 5 small flowers grow in erect clusters from the upper leaf axils (between the leaf and stem). Each flower is 5-parted, 1/8 inch long, with a deep lobe. The petals and petal-like sepals are joined at the base with the outer 3 longer than the inner 2.


Leaf and Stem Characteristics

Leaf Color: Yellowish-green, bluish-green     Leaf Type: Simple     Leaf Shape: Narrow     Leaf Margin: Smooth     Leaf Attachment: Alternate     Leaves Clasp: N
Hairs: No     Spines: N
Leaf Description: Stems are smooth often growing to about 3 feet but may be as tall as 6 feet. Leaves are flat and narrow with thickened joints or nodes at the base. Branch leaves are much smaller than those on the stem. A sheath (ocrea) is found at the base of the leaf.


Fruit and Seed Characteristics

Fruit Color: Dark brown to black   
Fruit Type: Achene
Fruit Notes: Fruit is about 1/8 inch, dry, oval, 3-angled, smooth to rough, shiny or dull, sometimes with small rounded projections on its surface. Fruit is enclosed in or longer than the petals and sepals. Late season fruits are common and larger growing to 3/4 inch.
Seed Notes: Each fruit produces 1 seed. The fruit does not split open to release the seed when mature.



  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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