Persicaria pensylvanica

(Linnaeus) M. Gómez

Anales Inst. Segunda Enseñ. 2: 278. 1896.

Common names: Pennsylvania smartweed renouée de Pennsylvanie
Basionym: Polygonum pensylvanicum Linnaeus Sp. Pl. 1: 362. 1753
Synonyms: Persicaria mississippiensis (Stanford) Small Persicaria pensylvanica var. dura (Stanford) C. F. Reed Polygonum omissum 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
Treatment appears in FNA Volume 5. Treatment on page 588. Mentioned on page 582, 583, 589.

Plants annual, 1–20 dm; roots also occasionally arising from basal nodes; rhizomes and stolons absent. Stems ascending to erect, simple or branched, ribbed, glabrous or appressed-pubescent distally, eglandular or stipitate-glandular distally. Leaves: ocrea brownish, cylindric, 5–20 mm, chartaceous, base inflated, margins truncate, eciliate or ciliate with bristles to 0.5 mm, surface glabrous or appressed-pubescent, eglandular; petiole 0.1–2(–3) cm, glabrous or appressed-pubescent; blade sometimes with dark triangular or lunate blotch adaxially, narrowly to broadly lanceolate, 4–17(–23) × (0.5–)1–4.8 cm, base tapered to cuneate, margins antrorsely scabrous, apex acuminate, faces glabrous or appressed-pubescent, eglandular or glandular-punctate abaxially and occasionally adaxially. Inflorescences terminal and axillary, erect or rarely nodding, uninterrupted, 5–50 × 5–15 mm; peduncle 10–55(–70) mm, glabrous or pubescent, usually stipitate-glandular; ocreolae overlapping, margins eciliate or ciliate with bristles to 0.5 mm. Pedicels ascending, 1.5–4.5 mm. Flowers 2–14 per ocreate fascicle, homostylous; perianth greenish white to roseate, glabrous, not glandular-punctate, accrescent; tepals 5, connate ca. 1/4–1/3 their length, obovate to elliptic, 2.5–5 mm, veins prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 6–8, included; anthers yellow, pink, or red, elliptic; styles 2(–3), connate at bases. Achenes included or apex exserted, brown to black, discoid or, rarely, 3-gonous, without central hump on 1 side, 2.1–3.4 × 1.8–3 mm, shiny, smooth. 2n = 88.

Phenology: Flowering May–Dec.
Habitat: Moist, disturbed places, ditches, riverbanks, cultivated fields, shorelines of ponds and reservoirs
Elevation: 0-1800 m


V5 1200-distribution-map.gif

N.B., Nfld. and Labr. (Nfld.), N.S., Ont., Que., Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., W.Va., Wis., Wyo., South America (Ecuador), Europe (England, Spain).


Persicaria pensylvanica is a morphologically variable allotetraploid, with P. lapathifolia probably one of the parents (L. L. Consaul et al. 1991). Three or four varieties (under Polygonum) often have been accepted in North American floras; the characters on which these are based vary greatly within and among populations. J. W. Taylor-Lehman (1987) concluded that Polygonum pensylvanicum is best treated as a polymorphic species without infraspecific taxa, based on specimens primarily from Ohio. The heterostylous Persicaria bicornis often is included in P. pensylvanica. A single chromosome count of 2n = 22 reported by Á. Löve and D. Löve (1982), which could not be confirmed by Consaul et al. because the voucher could not be found, is excluded. Flowers with three styles and trigonous achenes are produced; they are exceedingly rare and probably mostly overlooked. Several Native American tribes prepared infusions and decoctions from P. pensylvanica, which they used as drugs for humans and horses (D. E. Moerman 1998).

Lower Taxa

... more about "Persicaria pensylvanica"
Harold R. Hinds† +  and Craig C. Freeman +
(Linnaeus) M. Gómez +
Polygonum pensylvanicum +
Pennsylvania smartweed +  and renouée de Pennsylvanie +
N.B. +, Nfld. and Labr. (Nfld.) +, N.S. +, Ont. +, Que. +, Ala. +, Alaska +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Del. +, D.C. +, Fla. +, Ga. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Mont. +, Nebr. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Okla. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Utah +, Vt. +, Va. +, W.Va. +, Wis. +, Wyo. +, South America (Ecuador) +, Europe (England +  and Spain). +
0-1800 m +
Moist, disturbed places, ditches, riverbanks, cultivated fields, shorelines of ponds and reservoirs +
Flowering May–Dec. +
Anales Inst. Segunda Enseñ. +
taylor-lehman1987a +
Persicaria mississippiensis +, Persicaria pensylvanica var. dura +, Polygonum omissum +, Polygonum pensylvanicum var. durum +, Polygonum pensylvanicum var. eglandulosum +, Polygonum pensylvanicum var. laevigatum +, Polygonum pensylvanicum var. nesophilum +  and Polygonum pensylvanicum var. rosiflorum +
Persicaria pensylvanica +
Persicaria sect. Persicaria +
species +