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Persicaria pensylvanica

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 pensylvanica (L.) M. Gómez
Habit: Annual, rhizomes, stolons 0. Stem: ascending to erect, 10--200 cm; glabrous or appressed-hairy distally, glands 0. Leaf: ocrea 5--20 mm, cylindric, brown, margin truncate, glabrous or ciliate, bristles 0 or < 0.5 mm, surface glabrous or appressed-hairy, not gland-dotted; petiole 0.1--2(3) cm; blade 4--17(20) cm, (0.5)1--4.8 cm wide, narrowly to widely lanceolate, glabrous or appressed-hairy, +- gland-dotted abaxially, occasionally adaxially, adaxially dark-blotched or not, base tapered to wedge-shaped, tip acuminate. Inflorescence: axillary, terminal, erect, dense, not interrupted; peduncle glands +- stalked; bractlets overlapped; pedicels ascending, 1.5--4.5 mm. Flower: perianth 2.5--5 mm, bell-shaped, +- enlarging, glabrous, not gland-dotted, white to pink, lobes 5, obovate to elliptic, veins prominent, not anchor-shaped, tips obtuse to rounded; stamens 6--8, included, anthers yellow, pink, or red; styles 2(3), fused basally. Fruit: included or exserted, 2--3.4 mm, 1.8--3 mm wide, lens-shaped or 3-angled, brown to black, shiny, smooth. Chromosomes: 2n=88.
Ecology: Moist disturbed places, drying ponds, riverbanks, fields; Elevation: +- 30 m. Bioregional Distribution: e ScV, expected elsewhere; Distribution Outside California: native to eastern United States, introduced otherwise in North America, Europe. Flowering Time: May--Dec Note: Variable, of hybrid origin, possibly with Persicaria lapathifolia as one parent.
Synonyms: Polygonum pensylvanicum L.; Persicaria mississippiensis (Stanford) Small; Persicaria pensylvanica var. dura (Stanford) C.F. Reed; Polygonum omissum Greene; Polygonum pensylvanicum var. durum Stanford; Polygonum pensylvanicum var. eglandulosum Myers; Polygonum pensylvanicum var. laevigatum Fernald; Polygonum pensylvanicum var. nesophilum Fernald; Polygonum pensylvanicum var. rosiflorum Norton
eFlora Treatment Author: Mihai Costea
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Citation for this treatment: Mihai Costea 2016. Persicaria pensylvanica, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 29, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on April 29, 2016.

Persicaria pensylvanica
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© 2003 George W. Hartwell

More photos of Persicaria pensylvanica in CalPhotos

Geographic subdivisions for Persicaria pensylvanica:
e ScV, expected elsewhere;
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.