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false water pepper, false water-pepper smartweed, mild waterpepper, renouée faux-poivre-d'eau, swamp smartweed, water-pepper

heartweed, lady's-thumb, lady's-thumb smartweed, redshank, renouée persicaire, spotted lady's-thumb

Habit Plants perennial, 1.5–10 dm; roots also often arising from proximal nodes; rhizomes often present. Plants annual, (0.5–)1–7(–13) dm; roots also often arising from proximal nodes; rhizomes and stolons absent.
Stems

decumbent to ascending, usually branched, without noticeable ribs, glabrous or obscurely strigose distally.

procumbent, decumbent, ascending, or erect, simple or branched, without obvious ribs, glabrous or appressed-pubescent.

Leaves

ocrea brown, cylindric, 5–23 mm, chartaceous, base inflated, margins truncate, ciliate with bristles (2–)4–10 mm, surface glabrous or strigose, not glandular-punctate;

petiole 0.2–2 cm, glabrous or strigose;

blade without dark triangular or lunate blotch adaxially, broadly lanceolate to linear-lanceolate, 5–25 × 0.4–3.7 cm, base tapered or acute, margins antrorsely appressed-pubescent, apex acuminate, faces glabrous or appressed-pubescent along midveins and sometimes on faces, usually punctate abaxially.

ocrea light brown, cylindric, 4–10(–15) mm, chartaceous, base inflated, margins truncate, ciliate with hairs 1–3.5(–5) mm, surface glabrous or strigose, rarely with spreading hairs, not glandular-punctate;

petiole 0.1–0.8 cm, glabrous or strigose, leaves sometimes sessile;

blade often with dark triangular or lunate blotch adaxially, lanceolate to narrowly ovate, (1–)5–10(–18) × (0.2–)1–2.5(–4) cm, base tapered or cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or strigose, especially along midveins, sometimes glandular-punctate abaxially.

Inflorescences

terminal, sometimes also axillary, erect, uninterrupted or interrupted proximally, 30–80 × 2–5 mm;

peduncle 10–30 mm, glabrous or strigose;

ocreolae overlapping distally, often not overlapping proximally, margins ciliate with bristles to 2(–3) mm.

terminal and axillary, erect, usually uninterrupted, 10–45(–60) × 7–12 mm;

peduncle 10–50 mm, glabrous or, rarely, pubescent;

ocreolae overlapping or sometimes interrupted proximally, margins ciliate with bristles 0.2–1.3(–2) mm.

Pedicels

ascending, 1–1.5 mm.

ascending, 1–2.5 mm.

Flowers

bisexual or unisexual and staminate, 2–6 per ocreate fascicle, homostylous;

perianth roseate proximally, roseate, white, or greenish white distally, not glandular-punctate or sometimes glandular-punctate with punctae on tubes and inner tepals, scarcely accrescent;

tepals 5, connate ca. 1/3–1/2 their length, obovate, 2.5–4 mm in bisexual flowers, 1.5–2.5 mm in staminate flowers, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded;

stamens 8, included or exserted in staminate flowers;

anthers pink or red, elliptic to ovate;

styles 3, connate near middle.

4–14 per ocreate fascicle, homostylous;

perianth greenish white proximally and roseate distally or entirely roseate, not glandular-punctate, scarcely accrescent;

tepals 4–5, connate ca. 1/3 their length, obovate, 2–3.5 mm, veins prominent, not anchor-shaped, margins entire, apex obtuse to rounded;

stamens 4–8, included;

anthers yellow or pink, ovate;

styles 2–3, connate proximally.

Achenes

included or apex exserted, brown to brownish black or black, 3-gonous, 1.5–3 × 1–2.3 mm, shiny, smooth.

included or apex exserted, brownish black to black, discoid or biconvex to 3-gonous, (1.9–)2–2.7 × (1.5–) 1.8–2.2 mm, shiny, smooth.

2n

= 44.

Persicaria hydropiperoides

Persicaria maculosa

Phenology Flowering Jun–Nov. Flowering Mar–Nov.
Habitat Wet banks and clearings, shallow water, marshes, moist prairies, ditches Weedy, moist semiwaste to cultivated areas
Elevation 0-1500 m (0-4900 ft) 0-2500 m (0-8200 ft)
Distribution
from FNA
AK; AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; BC; NB; NS; ON; QC; Mexico; Central America; South America
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AL; AR; AZ; 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; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK; YT; SPM; Africa; Greenland; Eurasia; Pacific Islands (New Zealand) [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

The extreme variability in Persicaria hydropiperoides is reflected in its extensive synonymy. Among the segregates most often recognized in floras and checklists is P. opelousana, which C. B. McDonald (1980) showed to be broadly sympatric and highly interfertile with P. hydropiperoides. Consistent with this conclusion, R. S. Mitchell (1971) found that P. hydropiperoides and P. opelousana are unique among native North American smartweeds in consistently possessing multicellular plate-glands on the abaxial surface of their leaves. Such glands also are found on P. maculosa, an introduced European species.

Herbarium specimens of Persicaria hydropiperoides sometimes are misidentified as P. maculosa, especially when the roots are missing. The former species may be distinguished reliably by its achenes all trigonous (trigonous and biconvex achenes are mixed in the inflorescences of P. maculosa) and bristles on the margins of the ocreae that average longer. M. L. Fernald (1922c) reported hybrids with P. robustior from Nova Scotia.

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

An allozyme study by L. L. Consaul et al. (1991) provided evidence of the allotetraploid origin of Persicaria maculosa, with P. lapathifolium as one of the parents. Plants with stems spreading-hairy and peduncles stipitate-glandular have been named P. maculosa subsp. hirsuticaulis (Danser) S. Ekman & Knutsson. Material referable to this subspecies has not been seen among North American specimens. Hybrids between P. maculosa and P. minor have been documented in Europe (R. H. Roberts 1977).

The Cherokee, Chippewa, and Iroquois prepared simple or compound decoctions of Persicaria maculosa, which they used as dermatological, urinary, gastrointestinal, and veterinary aids, for heart medicine, and as an analgesic (D. E. Moerman 1998).

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

Source FNA vol. 5, p. 585. FNA vol. 5, p. 593.
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. hydropiper, 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. meisneriana, P. minor, P. nepalensis, P. orientalis, P. pensylvanica, P. perfoliata, P. punctata, P. robustior, P. sagittata, P. setacea, P. virginiana, P. wallichii
Synonyms Polygonum hydropiperoides, P. opelousana, P. paludicola, Polygonum hydropiperoides var. adenocalyx, Polygonum hydropiperoides var. asperifolium, Polygonum hydropiperoides var. breviciliatum, Polygonum hydropiperoides var. bushianum, Polygonum hydropiperoides var. digitatum, Polygonum hydropiperoides var. opelousanum, Polygonum hydropiperoides var. psilostachyum, Polygonum opelousanum, Polygonum opelousanum var. adenocalyx Polygonum persicaria, P. fusiformis, P. vulgaris, Polygonum fusiforme, Polygonum persicaria var. ruderale, Polygonum puritanorum
Name authority (Michaux) Small: Fl. S.E. U.S., 378. (1903) Gray: Nat. Arr. Brit. Pl. 2: 269. (1822)
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