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

Asiatic smartweed, Asiatic tearthumb, devil's-tail, devil's-tail or giant climbing tearthumb, giant climbing tearthumb, mile a minute, mile-a-minute weed

Habit Plants perennial, 1.5–10 dm; roots also often arising from proximal nodes; rhizomes often present. Plants annual, 10–20(–70) dm; roots not also arising from proximal nodes.
Stems

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

scandent, ribbed, glabrous, often glaucous;

prickles 0.5–1 mm.

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 green, plane to broadly funnelform, 9–14 mm, at least some foliaceous, base inflated or not, without prickles, margins oblique, eciliate, surface glabrous, glaucous;

petiole 4.5–8 cm;

blade triangular, 4–7 × 4.5–9 cm, base truncate to cordate, usually peltate, margins entire, sparsely retrorsely prickly, apex acuminate, faces glabrous, usually glaucous 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.

capitate or spikelike, uninterrupted, 5–12 × 5–10 mm;

peduncle 10–50 mm, retrorsely prickly;

ocreolae overlapping, margins eciliate.

Pedicels

ascending, 1–1.5 mm.

mostly ascending, 1–3 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.

1–3 per ocreate fascicle;

perianth greenish white, glabrous, accrescent, becoming fleshy and blue in fruit;

tepals 5, connate to ca. 1/3 their length, broadly elliptic, 2–3.5 mm, apex acute to obtuse;

stamens (6–)8, filaments distinct, free;

anthers pinkish, ovate;

styles 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, black or reddish black, spheroidal, 3–3.5 × 3–3.5 mm, shiny, smooth.

Persicaria hydropiperoides

Persicaria perfoliata

Phenology Flowering Jun–Nov. Flowering Jun–Oct.
Habitat Wet banks and clearings, shallow water, marshes, moist prairies, ditches Thickets, streams banks, pastures, forest edges, roadsides, railroad embankments, other moist, disturbed sites
Elevation 0-1500 m (0-4900 ft) 0-300 m (0-1000 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
CT; DC; DE; MD; MS; NJ; NY; OH; OR; PA; RI; VA; WV; Asia [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.)

Persicaria perfoliata is an aggressive, fast-growing pest in its native range and in North America. At least some introductions appear to be through the nursery trade (J. C. Hickman and C. S. Hickman 1978; R. E. Riefener 1982). It was collected once in 1954 in British Columbia, but that population did not persist.

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

Source FNA vol. 5, p. 585. FNA vol. 5, p. 577.
Parent taxa Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon
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. maculosa, P. meisneriana, P. minor, P. nepalensis, P. orientalis, P. pensylvanica, 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 arifolium var. perfoliatum, Polygonum perfoliatum
Name authority (Michaux) Small: Fl. S.E. U.S., 378. (1903) (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919)
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