Persicaria lapathifolia |
Persicaria nepalensis |
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common knotweed, curltop knotweed, curltop ladysthumb, curlytop knotweed, dock-leaf smartweed, pale smartweed, renouée à feuilles de patience, willow weed |
Nepalese knotweed, Nepalese smartweed |
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Habit | Plants annual, (0.5–)1–10 dm; roots also sometimes arising from proximal nodes; rhizomes and stolons absent. | Plants annual, 3–5 dm; roots also often arising from proximal nodes. |
Stems | ascending to erect, simple or branched, scarcely ribbed, glabrous or, rarely, appressed-pubescent distally, sometimes glandular-punctate or stipitate-glandular distally. |
decumbent to ascending, glabrous except for fleshy, retrorse, whitish hairs 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 brownish or hyaline, cylindric to funnelform, 4–10 mm, chartaceous, base inflated or not, margins oblique, eciliate, surface glabrous or with bristlelike hairs proximally; petiole 0.1–3 cm, winged to base, leaves sometimes sessile; blade ovate-deltate, 1.5–5 × 1–4 cm, base rounded to truncate, margins glabrous or scabrous, apex acute, faces pilose and glandular-punctate abaxially, glabrous adaxially. |
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, 5–10 × 5–10 mm; peduncle 2–20 mm, apex stipitate-glandular; ocreolae overlapping, margins eciliate. |
Pedicels | ascending, 0.5–2.3 mm. |
mostly ascending, 0.1–1 mm, flowers sometimes sessile. |
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. |
1–2 per ocreate fascicle; perianth white to pink or lavender, urceolate, glabrous, scarcely accrescent; tepals 4(–5), oblong to broadly elliptic, 2.5–3 mm, apex acute to obtuse; stamens (5–)8, filaments distinct, free; anthers purplish black, elliptic; styles 2, 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, dark brown to black, biconvex, 1.5–2 × 1–1.5 mm, dull, minutely punctate. |
2n | = 22. |
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Persicaria lapathifolia |
Persicaria nepalensis |
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Phenology | Flowering (Apr-)Jul–Nov. | Flowering Jul–Oct. |
Habitat | Moist places, roadsides, floodplains, waste places, cultivated fields | Disturbed sites, gravel bars in lowland zone |
Elevation | 0-1500(-1800) m (0-4900(-5900) ft) | 0-900 m (0-3000 ft) |
Distribution |
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)
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CT; FL; MA; NY; PA; BC; Asia [Introduced in North America; introduced also in Europe, Africa] |
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.) |
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Source | FNA vol. 5, p. 589. | FNA vol. 5, p. 579. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Cephalophilon |
Sibling taxa | ||
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 nepalense |
Name authority | (Linnaeus) Gray: Nat. Arr. Brit. Pl. 2: 270. (1822) | (Meisner) H. Gross: Bot. Jahrb. Syst. 49: 277. (1913) |
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