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Persicaria amphibia

Higher Taxonomy
Family: PolygonaceaeView DescriptionDichotomous Key
Habit: Annual to shrub [tree]. Stem: nodes swollen or not. Leaf: simple, basal or cauline, generally alternate; ocreae present or 0, generally scarious, persistent or not. Inflorescence: flower clusters in axillary to terminal cyme-, panicle-, raceme-, spike-, umbel- or head-like arrangements, entire inflorescence or main inflorescence branches generally subtended by bracts ("inflorescence bracts"); peduncles present or 0; flower clusters in Eriogoneae-Eriogonoideae subtended by involucre of >= 1 free or +- fused, sometimes awn-tipped bracts ("involucre bracts") or, in Polygonoideae and rarely in Eriogonoideae, not (if bracts completely fused, involucre "tubular"); pedicels in Eriogoneae each often subtended by 2 free, transparent, linear bractlets or in Polygonoideae all subtended by 2+ fused, membranous, wide bractlets. Flower: generally bisexual, small, 1--200 per node; perianth parts 2--6, generally in 2 whorls, free or basally fused, generally petal-like, often +- concave adaxially, often darker at midvein, often turning +- red or +- brown in age; stamens [1]3 or 6--9 in 2 whorls; ovary superior, 1-chambered, ovule 1, styles 1--3. Fruit: achenes, included in or exserted from perianth, generally 3-angled, ovoid or elliptic, generally glabrous.
Genera In Family: 48 genera, +- 1200 species: worldwide, especially northern temperate; some cultivated for food (Coccoloba, sea-grape; Fagopyrum, Rheum, Rumex) or ornamental (Antigonon, lovechain; Coccoloba; Muehlenbeckia; Persicaria; Polygonum), a few timbered (Coccoloba; Triplaris). Several (Emex; Fallopia; Persicaria; Polygonum; Rumex) are weeds. Note: Treatment of genera in Eriogonoideae based on monographic work of James L. Reveal. Involucre number throughout is number (1--many) per ultimate grouping, at tips of ultimate branches; flower number is per flower cluster or involucre, unless otherwise stated. Fagopyrum esculentum Moench not naturalized, considered an historical waif (or garden weed +- presently), therefore not treated.
eFlora Treatment Author: Mihai Costea, except as noted
Scientific Editor: Thomas J. Rosatti, Bruce G. Baldwin.
Genus: PersicariaView DescriptionDichotomous Key

Common Name: SMARTWEED
Habit: Annual, perennial herb, rhizomed or stoloned. Stem: prostrate to erect, ribbed or +- so or not, glabrous or hairy, generally with adventitious roots. Leaf: cauline, alternate, petioled or not; ocrea papery, rarely +- leaf-like, opaque, persistent or disintegrating, glabrous to variously hairy; blade lanceolate or ovate to hastate or sagittate, entire. Inflorescence: axillary, terminal, generally spike-like; flowers 1--14; peduncle present, pedicels present [or 0]. Flower: bisexual or functionally +- unisexual, base not stalk-like; perianth not or +- enlarging, bell-shaped (urn-shaped, rotate), glabrous, gland-dotted or not, green-white, white, pink, or red; perianth parts 4--5, fused 1/4--2/3, outer 2 > inner 2 or 3; stamens 5--8, filaments free, cylindric, thread-like, glabrous, outer fused to perianth tube or not, anthers elliptic to ovate, yellow, pink, or red; styles 2--3, erect to reflexed, free or fused, stigmas head-like. Fruit: included or exserted, brown or dark-brown to black, not winged, discoid, lens-shaped, or 3-angled. Seed: embryo curved.
Etymology: (Latin: persica, peach, aria, pertaining to; from resemblance of leaves of some species to those of peach)
eFlora Treatment Author: Mihai Costea
Persicaria amphibia (L.) Delarbre
Habit: Perennial herb, rhizomed or stoloned. Stem: prostrate to erect, 20--120 (300) cm, glabrous or hairy, +- ribbed. Leaf: ocrea 5--50 mm, +- cylindric, leaf-like distally or not, tan to dark-brown, margins truncate to oblique, glabrous or ciliate, bristles 0.5--4.5 mm, surface glabrous or appressed-hairy, not gland-dotted; petiole 0--3(7) cm; blade 2--15(20) cm, 1--6(8) cm wide, ovate- or lance-oblong to elliptic, glabrous or sparsely strigose, generally not gland-dotted, adaxial dark blotch 0, base tapered to acute or rounded (cordate), tip acute to acuminate. Inflorescence: 1 or paired, terminal, ascending to erect, generally uninterrupted, 10--150 mm, 8--20 mm wide; peduncle 10--500 mm, glabrous or strigose, often stalked-glandular; bractlets generally overlapped; pedicels ascending, 0.5--1.5 mm; flowers 1--4. Flower: perianth 4--6 mm, bell-shaped, +- enlarging, not gland-dotted, pink to red, parts 5, obovate to elliptic, veins prominent, not anchor-shaped, tip rounded to acute; stamens 5, included or exserted, anthers pink or red; styles 2, included or exserted, fused +- 2/3. Fruit: included, 2--3 mm, 1.6--2.6 mm wide, lens-shaped, dark-brown, smooth or minute-granular, shiny or dull. Chromosomes: 2n=66,132.
Ecology: Shallow lakes, streams, shores; Elevation: < 3000 m. Bioregional Distribution: CA (exc e DMoj); Distribution Outside California: northern hemisphere; naturalized in South America, southern Africa. Flowering Time: Jun--Nov Note: High variation +- correlated with ecology, but +- continuous so that varieties not recognized.
Synonyms: Persicaria amphibia var. emersa (Michx.) J.C. Hickman; Persicaria amphibia var. stipulacea (N. Coleman) H. Hara; Polygonum amphibium L.; Polygonum amphibium var. emersum Michx.; Polygonum amphibium var. stipulaceum N. Coleman; Persicaria coccinea (Muhl. ex Willd.) Greene
Jepson eFlora Author: Mihai Costea
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Persicaria amphibia

botanical illustration including Persicaria amphibia

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Citation for this treatment: Mihai Costea 2012, Persicaria amphibia, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 26, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on May 26, 2024.

Persicaria amphibia
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©2019 Barry Breckling
Persicaria amphibia
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©2011 Barry Breckling
Persicaria amphibia  
var. stipulacea
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©2016 Keir Morse
Persicaria amphibia
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©2005 Steve Matson
Persicaria amphibia
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©2019 Neal Kramer

More photos of Persicaria amphibia
in CalPhotos

Geographic subdivisions for Persicaria amphibia:
CA (exc e DMoj)
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).


Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).