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dotted knotweed, dotted smartweed, renouée ponctuée, water smartweed

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 annual or perennial, 1.5–12 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

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

scandent, ribbed, glabrous, often glaucous;

prickles 0.5–1 mm.

Leaves

ocrea brown, cylindric, (4–)9–18 mm, chartaceous, base inflated, margins truncate, ciliate with bristles 2–11 mm, surface glabrous or strigose, glandular-punctate;

petiole 0.1–1 cm, glandular-punctate, leaves sometimes sessile;

blade without dark triangular or lunate blotch adaxially, lanceolate to lanceolate-ovate or subrhombic, 4–10(–15) × 0.6–2.4 cm, base tapered or cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or scabrous along midveins, glandular-punctate.

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

mostly terminal, sometimes also axillary, erect, interrupted, 50–200 × 4–8 mm;

peduncle 30–60 mm, glabrous, glandular-punctate;

ocreolae mostly not overlapping, margins mostly ciliate with bristles to 2 mm.

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

peduncle 10–50 mm, retrorsely prickly;

ocreolae overlapping, margins eciliate.

Pedicels

ascending, 1–4 mm.

mostly ascending, 1–3 mm.

Flowers

2–6 per ocreate fascicle, homostylous;

perianth greenish proximally, white distally, rarely tinged pink, glandular-punctate with punctae ± uniformly distributed, scarcely accrescent;

tepals 5, connate ca. 1/3 their length, obovate, 3–3.5 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.

1–3 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, brownish black, usually 3-gonous, rarely biconvex, (1.8–)2.2–3.2 × 1.5–2.2 mm, shiny, smooth.

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

2n

= 44.

Persicaria punctata

Persicaria perfoliata

Phenology Flowering Jun–Nov. Flowering Jun–Oct.
Habitat Shallow water, shores, marshes, floodplain forests 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
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; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; WY; HI; BC; MB; NB; NS; ON; PE; QC; SK; Mexico; West Indies (Puerto Rico); Central America (Guatemala); South America (Brazil)
[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

N. C. Fassett (1949) proposed a complicated classification for Persicaria punctata with 12 varieties in North America and South America. He also identified numerous specimens that he considered to be morphologically intermediate between various varieties. M. Dalci (1972) documented a wide range of phenotypic and genotypic variation throughout the range of P. punctata and extensive overlap in many of the features used by Fassett to distinguish varieties. Consequently, recognition of varieties does not seem warranted. Persicaria punctata and its close relatives P. robustior and P. glabra are unique among native North American smartweeds in possessing complex glands called valvate chambers in their epidermises. Persicaria punctata is confused most frequently with P. hydropiper; the achenes are diagnostic.

The Chippewa, Houma, and Iroquois prepared decoctions from leaves, flowers, and roots for use as analgesics as well as gastrointestinal, orthopedic, and psychological aids (D. E. Moerman 1998).

(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. 586. 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. hydropiperoides, P. lapathifolia, P. longiseta, P. maculosa, P. meisneriana, P. minor, P. nepalensis, P. orientalis, P. pensylvanica, P. perfoliata, 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 punctatum, Polygonum acre var. leptostachyum, Polygonum punctatum var. confertiflorum, Polygonum punctatum var. ellipticum, Polygonum punctatum var. leptostachyum, Polygonum punctatum var. parviflorum, Polygonum punctatum var. parvum Polygonum arifolium var. perfoliatum, Polygonum perfoliatum
Name authority (Elliott) Small: Fl. S.E. U.S., 379. (1903) (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919)
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