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common knotweed, curltop knotweed, curltop ladysthumb, curlytop knotweed, dock-leaf smartweed, pale smartweed, renouée à feuilles de patience, willow weed

r enouée robuste, stout dotted smartweed, stout smartweed

Habit Plants annual, (0.5–)1–10 dm; roots also sometimes arising from proximal nodes; rhizomes and stolons absent. Plants perennial, 3–20 dm; roots also sometimes arising from proximal nodes; rhizomes present, stolons sometimes present.
Stems

ascending to erect, simple or branched, scarcely ribbed, glabrous or, rarely, appressed-pubescent distally, sometimes glandular-punctate or stipitate-glandular distally.

ascending, usually branched proximally, scarcely ribbed, glabrous, glandular-punctate;

branches sometimes creeping and rooting at nodes.

Leaves

ocrea brownish, cylindric, 4–24(–35) mm, chartaceous, base inflated, margins truncate, eciliate or ciliate with bristles to 1 mm, surface glabrous, rarely strigose, eglandular;

petiole 0.1–1.6 cm, usually strigose, sometimes glabrous;

blade sometimes with dark triangular or lunate blotch adaxially, narrowly to broadly lanceolate, 4–12(–22) × (0.3–)0.5–4(–6) cm, base tapering to cuneate, margins antrorsely scabrous, apex acuminate, faces strigose on main veins, glabrous or tomentose abaxially, glandular-punctate abaxially.

ocrea light brown, cylindric, 10–15 mm, chartaceous, base inflated, margins truncate, ciliate with bristles 3–12 mm, surface strigose, glandular-punctate;

petiole 0.2–2 cm, glandular-punctate;

blade without dark triangular or lunate blotch adaxially, lanceolate to elliptic-lanceolate, 4–20 × 2–4.5 cm, base tapered, margins antrorsely strigose, apex acute to acuminate, faces glabrous or main veins scabrous, glandular-punctate.

Inflorescences

mostly terminal, sometimes also axillary, mostly arching or nodding, usually uninterrupted, 30–80 × 5–12 mm;

peduncle 2–25 mm, often stipitate-glandular;

ocreolae usually overlapping, margins eciliate or ciliate with bristles to 0.4 mm.

terminal and axillary, erect, uninterrupted, 20–80 × 5–10 mm;

peduncle 5–40 mm, glandular-punctate;

ocreolae usually overlapping, margins eciliate or proximal ones sometimes ciliate with bristles to 1 mm.

Pedicels

ascending, 0.5–2.3 mm.

ascending to spreading, 2–5 mm.

Flowers

4–14 per ocreate fascicle, homostylous;

perianth greenish white to pink, glabrous, not glandular-punctate or glandular-punctate with punctae mostly on tubes and inner tepals, scarcely accrescent;

tepals 4(–5), connate ca. 1/4–1/3 their length, obovate to elliptic, 2.5–3 mm, veins prominent, those of 2 or 3 outer tepals prominently bifurcate distally, anchor-shaped, margins entire, apex obtuse to rounded;

stamens 5–6, included;

anthers pink or red, elliptic;

styles 2(–3), connate at bases.

2–4 per ocreate fascicle, homostylous;

perianth greenish proximally, white distally, glandular-punctate with punctae ± uniformly distributed, slightly accrescent;

tepals 5, connate ca.1/3 their length, obovate, 3.2–4.2 mm, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded;

stamens 6–8, included;

anthers pink or red, elliptic;

styles 3, connate proximally.

Achenes

included or apex exserted, brown to black, discoid or, rarely, 3-gonous, 1.5–3.2 × 1.6–3 mm, shiny or dull, smooth.

included or apex exserted, dark brown to brownish black, 3-gonous, 2.7–3.6 × 2–2.5 mm, shiny, smooth.

2n

= 22.

Persicaria lapathifolia

Persicaria robustior

Phenology Flowering (Apr-)Jul–Nov. Flowering Jul–Oct.
Habitat Moist places, roadsides, floodplains, waste places, cultivated fields Peaty shores, often in water on coastal plain or near coast
Elevation 0-1500(-1800) m (0-4900(-5900) ft) 0-1500 m (0-4900 ft)
Distribution
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; NT; ON; PE; QC; SK; YT; SPM; Mexico; South America; Africa; Greenland; Asia; Europe; Pacific Islands (New Zealand)
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DE; FL; IN; KY; MA; MD; ME; MI; MO; NH; NJ; NY; OH; PA; RI; TX; VA; NS; ON; QC; Central America; South America; West Indies
[WildflowerSearch map]
[BONAP county map]
Discussion

Persicaria lapathifolia is a morphologically variable complex with more than two-dozen infraspecific taxa described in the New World and Old World. An allozyme study by L. L. Consaul et al. (1991) did not support recognition of elements often referred to Polygonum lapathifolium var. salicifolium or P. scabrum, which are synonymized here. Yang J. and Wang J. W. (1991) reached a similar conclusion regarding var. salicifolium and P. nodosum based on their morphometric analysis.

The Keres, Navajo, and Potawatomi prepared medicinal infusions with Persicaria lapathifolia, and the Zuni used decoctions made from the plants as cathartic and emetic drugs (D. E. Moerman 1998).

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

Persicaria robustior often is synonymized with P. punctata.

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

Source FNA vol. 5, p. 589. FNA vol. 5, p. 584.
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. hydropiperoides, 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. perfoliata, P. punctata, P. sagittata, P. setacea, P. virginiana, P. wallichii
Synonyms Polygonum lapathifolium, Polygonum incarnatum, Polygonum lapathifolium var. ovatum, Polygonum lapathifolium var. salicifolium, Polygonum linicola, Polygonum nodosum, Polygonum pensylvanicum var. oneillii, Polygonum scabrum, Polygonum tomentosum Polygonum punctatum var. robustius, P. punctata var. robustior, Polygonum punctatum var. majus, Polygonum robustius
Name authority (Linnaeus) Gray: Nat. Arr. Brit. Pl. 2: 270. (1822) (Small) E. P. Bicknell: Bull. Torrey Bot. Club 36: 455. (1909)
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