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Persicaria hydropiperoides

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
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.
Species In Genus: +- 100 species: +- worldwide. Etymology: (Latin: persica, peach, aria, pertaining to; from resemblance of leaves of some species to those of peach)

Persicaria hydropiperoides (Michx.) Small
Habit: Perennial herb, rhizomed. Stem: decumbent to ascending, 15--100 cm, glabrous or obscurely strigose distally. Leaf: ocrea 5--20 mm, cylindric, brown, margins truncate, ciliate, bristles (2)4--10 mm, surface glabrous or strigose, not gland-dotted; petiole 0.2--2 cm; blade 5--25 cm, 0.4--3.7 cm wide, linear- to widely lanceolate, glabrous or appressed-hairy on midveins, also on surfaces or not, generally abaxially gland-dotted, adaxial dark blotch 0, base tapered or acute, tip acuminate. Inflorescence: axillary, terminal, erect, generally uninterrupted, 30--80 mm, 2--5 mm wide; peduncle 10--30 mm, glabrous or strigose; bractlets overlapped distally, often not proximally; pedicels ascending, 1--1.5 mm; flowers 2--6. Flower: perianth (1.5) 2.5--4 mm, bell-shaped, +- enlarging, not gland-dotted, pink or white-+- green, lobes 5, obovate, veins prominent or not, not anchor-shaped, tips obtuse to rounded; stamens 8, included or exserted, anthers pink or red; styles 3, fused nearly 1/2. Fruit: included or exserted, 1.5--3 mm, 1--2.3 mm wide, 3-angled, brown to black, shiny, smooth. Chromosomes: 2n=40.
Ecology: Wet banks, shallow water, marshes, moist prairies; Elevation: < 1500 m. Bioregional Distribution: CA-FP, DSon; Distribution Outside California: to eastern North America, Mexico. Flowering Time: Jun--Oct Note: Confused with Persicaria maculosa (see key).
Synonyms: Polygonum hydropiperoides Michx.; Polygonum hydropiperoides var. asperifolia Stanford; Persicaria opelousana (Small) Small; Persicaria paludicola Small
eFlora Treatment Author: Mihai Costea
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botanical illustration including Persicaria hydropiperoides


Citation for this treatment: Mihai Costea 2016. Persicaria hydropiperoides, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on April 28, 2016.

Persicaria hydropiperoides
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© 2015 Barry Breckling
Persicaria hydropiperoides
click for enlargement
© 2005 George W. Hartwell
Persicaria hydropiperoides
click for enlargement
© 2015 Barry Breckling
Persicaria hydropiperoides
click for enlargement
© 2005 George W. Hartwell

More photos of Persicaria hydropiperoides in CalPhotos

Geographic subdivisions for Persicaria hydropiperoides:
CA-FP, DSon;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.