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common smartweed, marsh-pepper smartweed, marshpepper knotweed, mild water-pepper, renouée poivre-d'eau, smartweed, water-pepper, water-pepper smartweed

kiss-me-Over-the-garden-gate, Prince's-feather smartweed, princess-feather, renouée orientale

Habit Plants annual, 2–8(–10) dm; roots also often arising from proximal nodes; rhizomes and stolons absent. Plants annual, 6–25 dm; roots not also arising from proximal nodes; rhizomes and stolons absent.
Stems

decumbent to ascending or erect, branched, without noticeable ribs, glabrous, glandular-punctate.

erect, simple or branched distally, usually ribbed, strigose or glabrescent proximally, pilose to hirsute distally.

Leaves

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.

ocrea brownish proximally, green distally, narrowly funnelform, 10–20 mm, chartaceous proximally, foliaceous distally, rarely chartaceous throughout, base inflated or not, margins truncate, ciliate with bristles 1–3 mm, surface densely strigose to hispid, not glandular-punctate;

petiole 1–8.5(–14) cm, densely pilose to hirsute;

blade without dark triangular or lunate blotch adaxially, ovate, 6–25(–30) × 3–17 cm, base cordate to truncate, margins scabrous to ciliate, apex acuminate, faces minutely strigose to densely hirsute, especially along veins abaxially, not glandular-punctate.

Inflorescences

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.

mostly terminal, nodding or erect, uninterrupted, 10–150 × 8–18 mm;

peduncle 20–100 mm, hirsute;

ocreolae overlapping, margins ciliate with bristles 0.2–1 mm.

Pedicels

ascending, 1–3 mm.

ascending to spreading, 1–4 mm.

Flowers

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.

(1–)2–5 per ocreate fascicle, homostylous;

perianth roseate to red, glabrous, not glandular-punctate, slightly accrescent;

tepals 5, connate in proximal 1/3, obovate, 3–4.5 mm, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded;

stamens 6–8, included or exserted;

anthers pink or red, elliptic;

styles 2, connate proximally.

Achenes

included or apex exserted, brownish black, biconvex or 3-gonous, 1.9–3 × 1.5–2 mm, dull, minutely roughened.

included, dark brown to black, discoid, 2.5–3.5 × 3–3.5 mm, shiny to dull, smooth to minutely granulate.

2n

= 20.

Persicaria hydropiper

Persicaria orientalis

Phenology Flowering May–Nov. Flowering Jun–Oct.
Habitat Shorelines of lake and ponds, banks of streams and rivers, fens, forested wetlands, pastures, occasionally waste ground Moist waste places
Elevation 0-1500 m (0-4900 ft) 0-500 m (0-1600 ft)
Distribution
from FNA
AK; AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; SPM; Europe; nw Africa; Pacific Islands (Hawaii, New Zealand); Australia [Introduced in North America; introduced also in Asia]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WI; WV; NB; ON; QC; s Asia (India) [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Persicaria orientalis was introduced as a garden ornamental. It often persists around homesteads and barnyards, and occasionally escapes and becomes weedy in moist waste places. A collection made in 1853 by F. V. Hayden at Fort Pierre, South Dakota (MO), is assumed to have come from a cultivated plant.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 5, p. 590. FNA vol. 5, p. 591.
Parent taxa Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria
Sibling taxa
P. amphibia, P. arifolia, P. bicornis, P. bungeana, P. capitata, P. careyi, P. chinensis, P. glabra, P. hirsuta, P. hydropiperoides, P. lapathifolia, P. longiseta, P. maculosa, P. meisneriana, P. minor, P. nepalensis, P. orientalis, P. pensylvanica, P. perfoliata, P. punctata, P. robustior, P. sagittata, P. setacea, P. virginiana, P. wallichii
P. amphibia, P. arifolia, P. bicornis, P. bungeana, P. capitata, P. careyi, P. chinensis, P. glabra, P. hirsuta, P. hydropiper, P. hydropiperoides, P. lapathifolia, P. longiseta, P. maculosa, P. meisneriana, P. minor, P. nepalensis, P. pensylvanica, P. perfoliata, P. punctata, P. robustior, P. sagittata, P. setacea, P. virginiana, P. wallichii
Synonyms Polygonum hydropiper, Polygonum hydropiper var. projectum Polygonum orientale
Name authority (Linnaeus) Spach: Hist. Nat. Vég. 10: 536. (1841) (Linnaeus) Spach: Hist. Nat. Vég. 10: 537. (1841)
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