FloraFinder.org
Home   About Us   FAQ  
Searching   Image Use Plant Books
x
FloraFinder uses cookies only for correct operation. More info. Okay

Polygonum hydropiperoides Michx.

Mild water-pepper, mild water pepper

KingdomPlantaePlants, but not fungi, lichens, or algae
SubkingdomTracheobiontaVascular plants—plants with a “circulatory system” for delivering water and nutrients
DivisionMagnoliophytaFlowering plants, also known as angiosperms
ClassMagnoliopsidaDicotyledons—plants with two initial seed leaves
SubclassCaryophyllidaeCacti, many other succulents, carnivorous plants, and leadworts
OrderCaryophyllalesIncludes cacti, carnations, amaranths, ice plants, and many carnivorous plants
FamilyPolygonaceaeKnotweed or smartweed family
GenusPolygonumGreek poly, “many,” and gonu, “knee,” for the swollen jointed stems
SpecieshydropiperoidesHaving a resemblance to hydropiper

About plant names...

False waterpepper is a perennial native to North and South America, so named because it is easily confused with water pepper (Persicaria hydropiper). They often form mats along lake or pond margins.

Plants: Erect to sprawling perennials. Stems are green to red, 6-39″ (15-100 cm) long, but slender and with upper portions usually erect. (Compare to P. amphibium, with stems up to ⅜″ (1 cm) around, and more often sprawled along the surface of the water).

Leaves: Alternate, lanceolate, bristly, with smooth edges. Floating or upright, up to 4″ (10 cm) long × ⅜-⅞″ (1-2.5 cm), tapering to a sharp point. Leaf stalks (petioles) are less than ⅛″ (5 mm) long. Leaves are not mottled. Where they connect to the stem, there is a sheath called the ocrea typical of this genus. The ocrea is brown, cylindric, and ⅛-⅞″ (5-23 mm) long, with an inflated base, topped with hairs 1/16-⅜″ (2-10 mm).

Flowers: Greenish, pinkish, or white flowers form loose, elongated spikes 1-3″ (3-8 cm) long and 1/16-⅛″ (2-5 mm) around. The spikes are on peduncles ⅜-1″ (1-3 cm) long.

Fruits: Dry, hard, smooth, shiny achenes each contain a single seed. They are 1/32-⅛″ (1.5-3 mm) long, and three-sided.

Some similar species:

 

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

9/15/2012 · Mt. Wachusett, Princeton, Mass­a­chu­setts · ≈ 15 × 10″ (39 × 26 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

9/15/2012 · Mt. Wachusett, Princeton, Mass­a­chu­setts · ≈ 12 × 8″ (31 × 20 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

9/15/2012 · Mt. Wachusett, Princeton, Mass­a­chu­setts · ≈ 17 × 12″ (44 × 29 cm)

 
Polygonum amphibium

Polygonum cespitosum
You are here
Polygonum hydropiperoides
Common Name

water smartweed

Oriental lady’s thumb

mild water-pepper
Plant Up to 9½′ (3 m) × ⅜″ (1 cm), sprawling or floating. Up to 3′ (91 cm) in size, sprawling or erect. 6-39″ (15-100 cm) long, but slender and with upper portions usually erect, erect to sprawling. Stems are green to red. (Compare to P. amphibium, with stems up to ⅜″ (1 cm) around, and more often sprawled along the surface of the water).
Flowers Pink, appearing in a thick oval cluster of tiny five-lobed flowers. The cluster is ¾-6″ (2-15 cm) long. Each individual flower is ⅛-3/16″ (4-5 mm) in diameter. Flowers appear June to September. Pink/white flower spikes are ¾-1½″ (1.9-3.8 cm) tall × 1/16-3/16″ (3-6 mm) thick, densely filled with individual flowers less than ¼″ (6.3 mm) in size. (By contrast, P. persicaria has flower stalks ⅛-⅜″ (6-12 mm) thick.) Flowers appear from June to October. Greenish, pinkish, or white flowers form loose, elongated spikes 1-3″ (3-8 cm) long and 1/16-⅛″ (2-5 mm) around. The spikes are on peduncles ⅜-1″ (1-3 cm) long.
Leaves Alternate, and often lanceolate, but they take on many other shapes. They may be floating or upright, with papery sheaths at leaf bases. They are ¾-8″ (2-20 cm) × ⅛-1¾″ (5-50 mm), with petioles 1/32-1″ (1-30 mm). They are not mottled. Alternate, elliptic to lanceolate, ¾-3″ (2-7.5 cm) × ⅜-1¼″ (1-3.5 cm), and pointed at the base and tip. Petioles are 1/32-⅛″ (1-5 mm). Leaves are not mottled. Alternate, lanceolate, bristly, with smooth edges. Floating or upright, up to 1¾-6″ (5-15 cm) × ⅜-⅞″ (1-2.5 cm), tapering to a sharp point. Petioles are less than ⅛″ (5 mm) long. Leaves are not mottled.
Stem Ocrea are ⅛-1¾″ (5-50 mm), with the upper part fringed with small hairs 0.5-4.5 mm long. Ocrea encompassing the joints are long-bristly, and ⅛-⅜″ (4-12 mm) long,, vs. less than ⅛″ (5 mm) for P. persicaria. Ocrea are brown, cylindric, and ⅛-⅞″ (5-23 mm) long, with an inflated base, topped with hairs 1/16-⅜″ (2-10 mm).
Fruit Tiny brown rounded achenes 1/16-⅛″ (2.5-3 mm) long. Each achene contains one seed. They appear from July to September. A black achene with a triangular cross section. Dry, hard, smooth, shiny achenes each contain a single seed. They are 1/32-⅛″ (1.5-3 mm) long, and three-sided.
Range/ Zones

Habitats Floating in ponds, streams, and marshes Common to invasive in disturbed habitats such as pastures, roadsides, and lawns. It is partial to wet areas. Often forming mats along lake or pond margins.
Type Wild Wild Wild

 

 
Polygonum lapathifolium

Polygonum persicaria
Common Name

nodding smartweed

lady’s thumb
Plant 2-5′ (60-152 cm) high, usually upright, some­times sprawling, with green or deep red hairless stems. Up to 3′ (91 cm) in height. Stems are openly branched and often reddish.
Flowers Greenish-white to pink, in columns about ¼-⅜″ (6.3-9.5 mm) in diameter and 1-3″ (2.5-7.6 cm) long. Numerous clusters may be upright, arched, or drooping. The tiny, individual flowers never actually open. Tiny pink and white flowers form groups of spikes ½-1½″ (1.3-3.8 cm) long. Flowers appear from June to July.
Leaves Alternate, typically lanceolate but variable in shape, fatter at the base and tapering to a sharp tip, 1¾-10″ (5-25 cm) × ½-1¾″ (1.5-5 cm). Petioles are ⅜-¾″ (1-2 cm). Leaves have tiny, hooklike hairs that make them feel rough. They are not mottled. Alternate, lanceolate to elliptic, 1-8″ (2.5-20 cm) long × ¼-2″ (6.3-50 mm) wide. Petioles are ⅛-¼″ (5-8 mm). Leaves often have a dark purplish triangular or lunate patch on them.
Stem The ocreas are brownish, tubular, ½-1″ (1.5-3 cm) long, with few or no hairs. Ocreas have hairs that extend up to 1/16″ (2 mm) from the top.
Fruit Egg-shaped, less than 1/16″ (2 mm) long, brown to black, glossy, containing a single seed. Brown to black, glossy, with one seed. They are roughly egg-shaped, but somewhat angular. Each fruit is less than 1/16″ (2 mm) long. Fruits appear from July to September.
Range/ Zones

USDA Zones: 4-8
Habitats Margins of water bodies, pastures, orchards, irrigated crop fields, and rice fields. Disturbed soils that are wet or seasonally wet, such as ditches, pastures, grain fields, and water edges.
Type Wild Wild

 

Online References:

Fortress.wa.gov

Www.backyardnature.net

Wikipedia

References:

Clemants, Steven; Gracie, Carol, Wildflowers in the Field and Forest, Oxford University Press, 2006, p. 76

Weakley, Alan S.; Ludwig, J. Christopher; Townsend, John F.; Crowder, Bland (Ed.), Flora of Virginia, Botanical Research Institute of Texas Press, 2013, p. 812

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

9/15/2012 · Mt. Wachusett, Princeton, Mass­a­chu­setts · ≈ 6 × 4″ (15 × 10 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/22/2012 · Squannacook River Wildlife Area, Townsend, Mass­a­chu­setts · ≈ 2 × 1′ (62 × 41 cm) ID is uncertain

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/18/2013 · Bemis Road, Townsend, Mass­a­chu­setts · ≈ 6 × 4″ (15 × 10 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

9/15/2012 · Mt. Wachusett, Princeton, Mass­a­chu­setts · ≈ 2 × 1′ (62 × 41 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/22/2012 · Squannacook River Wildlife Area, Townsend, Mass­a­chu­setts ID is uncertain

Persicaria hydropiperoides (Michx.) Small

Persicaria hydropiperoides (Michx.) Small var. breviciliata (Fernald) C.F. Reed

Persicaria hydropiperoides (Michx.) Small var. euronotora (Fernald) C.F. Reed

Persicaria hydropiperoides (Michx.) Small var. opelousana (Riddell ex Small) J.S. Wilson

Persicaria opelousana (Riddell ex Small) Small

Persicaria paludicola Small

Persicaria persicarioides (Kunth) Small

Polygonum hydropiperoides Michx. var. adenocalyx (Stanford) Gleason

Polygonum hydropiperoides Michx. var. asperifolium Stanford

Polygonum hydropiperoides Michx. var. breviciliatum Fernald

Polygonum hydropiperoides Michx. var. bushianum Stanford

Polygonum hydropiperoides Michx. var. digitatum Fernald

Polygonum hydropiperoides Michx. var. euronotorum Fernald

Polygonum hydropiperoides Michx. var. opelousanum (Riddell ex Small) Riddell ex W. Stone

Polygonum hydropiperoides Michx. var. psilostachyum H. St. John

Polygonum hydropiperoides Michx. var. strigosum (Small) Stanford

Polygonum opelousanum Riddell ex Small

Polygonum opelousanum Riddell ex Small var. adenocalyx Stanford

Polygonum persicarioides Kunth

 

Polygonum hydropiperoides description by Thomas H. Kent, last updated 8 Sep 2021.

© FloraFinder.org. All rights reserved.


 

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/18/2013 · Bemis Road, Townsend, Mass­a­chu­setts · ≈ 4½ × 7″ (12 × 18 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/18/2013 · Bemis Road, Townsend, Mass­a­chu­setts · ≈ 5 × 3½″ (13 × 8.8 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

9/15/2012 · Mt. Wachusett, Princeton, Mass­a­chu­setts · ≈ 11 × 7″ (27 × 18 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/18/2013 · Bemis Road, Townsend, Mass­a­chu­setts · ≈ 8 × 5″ (19 × 13 cm)

Polygonum hydropiperoides (mild water-pepper, mild water pepper)

8/22/2012 · Squannacook River Wildlife Area, Townsend, Mass­a­chu­setts ID is uncertain

Range:

About this map...