Persicaria pensylvanica
Persicaria hydropiper
Pennsylvania smartweed, pinkweed, renouée de pennsylvanie
common smartweed, marsh-pepper smartweed, marshpepper knotweed, mild water-pepper, renouée poivre-d'eau, smartweed, water-pepper, water-pepper smartweed
ascending to erect, simple or branched, ribbed, glabrous or appressed-pubescent distally, eglandular or stipitate-glandular distally.
decumbent to ascending or erect, branched, without noticeable ribs, glabrous, glandular-punctate.
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.
ocrea brown, cylindric or funnelform, (8–)10–15 mm, chartaceous, base inflated, margins truncate, ciliate with bristles 1–4 mm, surface glabrous or strigose, usually glandular-punctate;
petiole 0.1–0.8 cm, glandular-punctate, leaves sometimes sessile;
blade without dark triangular or lunate blotch adaxially, lanceolate to narrowly rhombic, (1.5–)4–10(–15) × 0.4–2.5 cm, base tapered or cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or scabrous along midveins, glandular-punctate, sometimes obscurely so adaxially.
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.
terminal and axillary, erect or nodding, interrupted or uninterrupted distally, 30–180 × 5–9 mm;
peduncle (0–)10–50 mm, sometimes absent on axillary inflorescences and flowers thus enclosed in ocreae, glabrous, glandular-punctate;
ocreolae not overlapping or overlapping distally, margins eciliate or ciliate with bristles to 1 mm.
ascending, 1.5–4.5 mm.
ascending, 1–3 mm.
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.
1–3(–5) per ocreate fascicle, homostylous;
perianth greenish proximally, white or pink distally, glandular-punctate with punctae ± uniformly distributed, scarcely accrescent;
tepals 4–5, connate ca. 1/3 their length, petaloid, obovate, 2–3.5 mm, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded;
stamens 6–8, included;
anthers pink or red, elliptic to ovate;
styles 2–3, connate proximally.
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.
included or apex exserted, brownish black, biconvex or 3-gonous, 1.9–3 × 1.5–2 mm, dull, minutely roughened.
= 88.
= 20.
Persicaria pensylvanica
Persicaria hydropiper
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).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
All parts of Persicaria hydropiper have an acrid, pepperlike taste. The plants have a long history of medicinal use in Europe, and the oily exudate produced in multicellular glands can cause skin irritation, hence the common name smartweed (R. S. Mitchell and J. K. Dean 1978). Some Native American tribes used P. hydropiper as a drug to treat a variety of ailments, and the Cherokee and Iroquois consumed it as food (D. E. Moerman 1998).
Herbarium specimens of Persicaria hydropiper often are misidentified as P. punctata. In addition to its minutely roughened and dull achenes, P. hydropiper differs from P. punctata frequently in bearing flowers enclosed in the ocreae, the inflorescences thus appearing somewhat leafy. By contrast, inflorescences of P. punctata generally appear terminal and leafless.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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WA - Local Web sites: CalFlora, CalPhotos, Flora NW, Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
